...I have already listed repeatedly what was deeper in SC5 on launch day.
The entire education system. The entire tourism system. The entire industry system. The entire density system. The entirety of the visuals. The entirety of the goals/conflicts systems. The entirety of the crime rate system. The entirety of the pollution systems. The entirety of the service systems. The entirety of the game's progression. The entirety of the region system (in CS it is not even possible to build two separate cities on one map and have them work together, they count as one city and all info views reflect that, and people aren't smart enough to work nearby or educate nearby etc). The entirety of the simulation timescale system.
Because CS works on a "people randomly decide to do things, and are randomly allowed to depending on how many agents are active" system, things like Education just don't work. Some houses might never go to elementary school before the kids are teens, and then they might never get to high school before they're adults. It takes generations for a building to count as educated because not every child ends up going ot school despite heavy school availability due to this awkward system of randomly letting people out of their homes. People count as having jobs even if they NEVER roll a desire to go to the job, and can go their entire life without leaving their house. In SimCity, there was an actual timescale to everything, and people with jobs ALL went to work, EVERY day, and kids with school access ALL went to school, EVERY day, and traffic reflected that, and you had to actually deal with rush hours and stuff. In Cities Skylines traffic is, at all times, a rough estimation of how things would go overall. It is never actually creating situations where there's everybody going home or going to work, or where school busses aren't making it through traffic (as they don't even exist) to get kids to school in time, or where the school's capacity isn't enough for all the kids in the city (instead, it's not enough for all the kids currently desiring to go to school at random).
CS has no goals and it has no situational conflicts. It has things like dead bodies that need picking up, and...that's about it. Everything else is pretty static. You add power and water and sewage and garbage and services as necessary, and there you go. You're doing good. Fires happen at random but they have next to no penalty. The unique building unlocks are sort of "goals" but they're not very well balanced and the rewards are not very well balanced, either. Meanwhile in Simcity disasters can happen, traffic can cause disasters, fires spread, etc.
In CS, when someone is upset about the lack of police coverage, they send a vague, uninteresting tweet to the internet and go about their day. You fix it, or don't, and life goes on. In SimCity, someone will throw up a giant bubble on their house that, when clicked, provides you with a detailed breakdown of what's wrong and how you can fix it (with humor thrown in) and offers the player the CHOICE to solve this problem and get bonuses if they do it in a timely manner and can prove, via the game's statistics, that they've made an impact- such as arresting a certain number of criminals, or recycling a certain amount of garbage, or going a certain number of days with no buildings burning down. You not only solve the problem, but you are actively rewarded for it, and moreso if you do a better job. You get an on-screen indicator of your progress towards a little mini-goal that directly tells you how well you solved the problem. If the problem isn't solved, something is wrong with your solution, and you may need to make changes.
Pollution in CS is "this building makes the ground dirty". Pollution in SimCity is air pollution AND ground pollution, and both take considerable effor to relieve. Removing a building in CS gets rid of pollution in a very short time. Completely clearing an area in SC and loading it with trees takes years upon years to remove pollution and it's devastating. You have to be very careful with pollution but it's next to inconsequential in CS.
In CS, Tourism consists of the following process: 1. Plop down a unique building 2. There is nothing else to do. Sometimes tourists visit it. They'll drive to the city or they'll come on a train or a plane. They magically manifest pocket cars from nowhere and clog the road a bit (assuming there's even enough to cause a problem) and they go to the building and then they leave. In SimCity, Tourism is its own entire section of the UI. You can gather tourists with stadiums, special buildings, landmarks, etc. You can dedicate parts of your city to tourism. Tourism needs hotels and generates hotels/motels/extravagant resorts based on wealth value. Tourists call for taxis if sufficient public transport doesn't exist. Tourists arrive in huge numbers. Tourists do not count towards an agent limit and they are not limited from entering the city if the number of agents in the city is too high, unlike CS where the limit is 65k and on a sufficiently packed city tourism is completely stalled as no tourist agents can actually exist. Tourists come at set times for events in the stadium, they clog the roads around it and leading to it and you have to plan for that. They stay at the event and it gathers tons of money for the city and then they make their way home and back out of town using your public transport systems or their own cars or taxis. They clog your infrastructure for a pre-planned amount of time at a set time on a set day and you have to deal with the issues that arise from that, and decide if it's worth testing your city's road structure at the risk of losing fire or police or ambulance response times.
In CS, if there's police stations and schools, there's no crime. In SimCity, if people are poor and jobless, thy will turn to crime despite a police presence and despite having an elementary school education, which is much more realistic and fun to deal with. In CS a police car driving by the house once a day is enough to deter crime, in SimCity crime has factors that go into why it is happening that have to be dealt with, which simply don't exist in CS on ANY level, like wealth value. There are no poor in CS. There are no rich. There are no problems associated with either of those as they do not exist.
In CS, to make a special industry, you make any industry, and then tap it to change it to something else. In SimCity, you have to plcae specific buildings to manage the industry, you have to have special processing plants and factories and services. You have to expand the functionality of these buildings. You have to manage things differently for each type of industry. You have to make the industries work together, or you can ismply export. Exporting is tough if you also have to import resources. One special industry usually requires at least one other to function with efficiency, whereas in CS you can plop any of them wherever you please and they subsist on their own without issue. In CS they do transfer goods between each other, and your commercial buildings will be a little upset if there's no generic industry, but not that upst, because without your input they automatically import from ghost cities that do not exist and have an infinite supply of anything you could ever need. In SC resources have to actually exist and make their way to town for things to keep running properly. In CS, if a car can't get somewhere, it magically poofs there. In SC, if a car can't get somewhere, shit goes down.
In CS, the population density is all sorts of screwed up. Small 2 bedroom homes house 8 adults and 3 teens and 4 children and 3 elders. What this means is that a school that SHOULD cover a 3 square mile area can only cover a half a square mile area because every single building in the area has 4-5x as many children as it logically should. In SimCity, if this sort of nonsense was happening (which it doesn't), you'd mitigate this problem with longer bus routes, more busses for the school, and more classrooms. In Cities Skylines your only option is to plop yet another identical school down nearby and call it a day.
In CS, making a university requires the following steps: 1. Place a university. In SimCity, a university is its own building, and then you create special buildings for different types of education like business, government, science...and then those buildings can work on projects to improve the city, give benefits to your special industry, require certain types of students, change hte way the generic industry in teh city functions...and you have to manage housing, including dorms, and nearby housing will even change depending on density to greek sorority/fraternity houses. it's on a whole separate level than CS. CS university system is like putting a cherry on a store bought cupcake, while SimCity's university system is like baking a 3 tier wedding cake from scratch. There's just no comparing the two. SimCity's has so much more depth that it makes your head spin.
In CS, the funding for individual buildings doesn't exist. In Simcity, funding for individual buildings is represented in terms of additional modules. In CS, to make a school have more capacity, you move a slider and it affects EVERY school on the ENTIRE map. In SimCity, to make a school have more capacity, you add another classroom, and it only affects that school and it only affects that school's costs. In CS, to make a police staton have more cars, you move a slider. It affects EVERY staton of EVERY type in the ENTIRE city. In SimCity, you add more squad cars, you add a helicopter platform, you add a better alarm system. It only affects the building you modified and the area that building works for.
In Cities Skylines, the buildings work for the entire city. They don't patrol set areas and will mindlessly wander across the entire map for no reason to "help" on the other side. The effective area doesn't exist, it's meaningless, and it ONLY shows you which houses benefit from happiness from the building. In SimCity, buildings have limits to how far their effects stretch in general, and the scale of operations has actual meaning. You can increase this scale, again, by upgrading the buildings.
In SimCity, as the value of an area goes up, it becomes more expensive to live in. As it becomes more expensive, more educate dpeople with better jobs move in. As they move in, they demand better jobs to keep their income and they will leave or not show up if those jobs don't exist at all. In Cities Skylines any random person will move into literally any area regardless of its land value and regardless of how much money they have (as there are no wealth values) and will complain. They'll gladly move into a nearly flooded area surrounded by abandoned homes and resting on top of severe ground pollution that has no water or power access, and THEN complaina bout those things, rather than NOT MOVING IN TO BEGIN WITH.
In Cities Skylines, recreational facilities consist of parks, parks, parks, some more parks, another type of park, a park, and a couple other parks. In SimCity, recreation includes stadiums, casinos, gardens, plazas, aquariums, skate parks, sports parks, zoos, museums, libraries, theaters...In Cities Skylines, plopping a park instantly makes everyone happy as hell because what else could tehy ever desire for fun besides some trees? In SimCity, a park does make people happy, but they also enjoy shopping and going out on the town. In CS, a park does nothing but provide a circle of happiness. In SimCity, parks lower crime by giving people something to do, they lower air pollution, and they have downsides such as potentially attracting homeless if your wealth levels are not kept in check and you don't have enough jobs and housing (none of these are issues in CS at all).
Need I go on? CS is unbelievably shallow in comparison.