I apologize for the wall of text, I absolutely love ringworlds in this game and real life (build multiple everytime) and want to clarify some things and potentially point out the direction I think they should be going in.
I'm curious if any of you have read Ringworld? It had a diameter of one million miles and the surface area of 3 million Earths. It is only 100 feet thick, and they used scrith (special alloy) to give it the strength it needed and to explain away science. The reason the civilizations on it weren't able to recover after something I won't ruin for you is because there were no metals in the soil since they were all used to produce said scrith. (Of course there were some outliers but they were reusing materials from the builders and they had help.) Larry Niven used roughly all the mass in our solar system as a basis to calculate how large he could create the Ringworld. And the thickness of the ringworld was a constant 100 feet even when there were hills/mountains/valleys/oceans and the bottom of the ringworld was an inverse topography of the surface. Because the amount of material needed was MASSIVE to create such a large structure.
I point out this information on ringworlds since it is easy to forget about the scale of these megastructure's when your in-game. Now as far as balance, there should absolutely not be a single mineral deposit in that system. If you notice there are some asteroid belts in game that don't have mineral deposits. This leads to the theory that only truly rich deposits are worth mining, so the handful of rocks that could possibly be left in the system after construction wouldn't be worth the power the ships used to get to them. I applaud the developers for staying true to this part of the lore and removing mineral deposits from ringworlds. And the fact that they made it an alloy cost is awesome since you need a special alloy to maintain the structural integrity of such a thin slice of a structure. Its not random rocks thrown together, its a specially designed material to create such an engineering marvel. And I absolutely don't believe they should bring the matter converter building back because I love the challenge of maximizing my mineral output late game and now that they have the market a matter converter is pointless too since you can just buy minerals (and yes that should be very costly to do).
I also love that they doubled the number of districts which helps in establishing what the ringworlds were built for, to house a LOT of people. However, the fact that ecumenopoli have been brought into the game (which I love and I like where they are at) deflates the usefulness of ringworlds. A size 25 ecumenopoli without modifiers creates 375 housing if its all city districts. One section of the ringworld again without modifiers creates 250 housing if its all city districts. The fact that ecumenopoli are so much easier to get and you can spam multiple in the mid game creating more housing than one ringworld section for almost the same cost of minerals(and without the jobs needed to turn those minerals into alloys) means there is no point to building ringworlds unless you need food/building slots (27,500 minerals to turn into alloys factoring in frame cost/section). A size 16 planet that is turned into an ecumenopoli will give the same level of housing as one ringworld section, take that in. Not to mention that ecumenopoli have special districts that are very powerful, and all this to say I think ecumenopoli are great right where they are at since they are huge investment and they are balanced against the current planets with their job/pop ratio.
However (and I may lose people here) if I am investing into a ringworld, it should be on a magnitude larger cost than a measly ecumenopoli. Thematically building a ringworld is the largest feat of engineering you can perform in Stellaris, and it should feel like it. Right now, having one is great but its not game changing and they don't have enough space (building slots) so you just keep making more. If you build a ringworld it should be the last one you ever need to build and you should never be able to fill it. There should always be room to build another building, and this is my biggest gripe with ringworlds right now. They don't feel big enough and you should be able to build enough buildings for everyone to have a job (and not be working energy or food districts). The whole point of a ringworld is to have essentially infinite space for a species (their purpose).
Now I am recommending upping the cost to build a ringworld since for the cost of about 6-8 battleships you can create a ringworld section (!?!?!). This is absurd, period. In return for upping the cost, we make them feel more impactful. Now I know the reason they are so weak right now is because if you increased the time to build them no one would ever have time to finish them and you don't want to throw the balance off compared to the other empires if someone had one. The solution to this would be reducing the usefulness of ringworlds you find in the galaxy (ruined and fallen empire) by making them almost as costly as building your own. You do this by making the cheapest part of the process the site and frame stage (which is realistic) and they could stay at current costs. You then increase the cost to build the sections which you can do one of two ways. You could increase the number of sections (which I think is unlikely since developers would also have to change the artwork/models) or you could directly increase the cost of building each section. By directly increasing the cost of each section you are maintaining the same pop growth speed and building speed they currently have which helps keep them balanced against other options.
No matter which way you increase their usefulness, they need to be at the same job/pop ratio as regular planets if you are building entirely city districts. You can go about that multiple ways but with the current model you are forced to build food and energy districts after you max out the jobs in the building slots. This is limiting their usefulness cause you don't need 100 districts per ringworld dedicated to food (I know there is energy but honestly trade has made that irrelevant). While I agree they should be able to make absurd amounts of food/energy they shouldn't be forced to if you want to make a metropolis for one of your sections. When an ecumenopoli makes a better capital than a ringworld, you have a problem.
So if you want to do a half fix, double their building slots and this would make them somewhat satisfactory. If you want to tackle them more seriously, double or triple the ringworld section cost and double the districts while quadrupling the building slots. This would make them feel far larger and more impactful when you get one. This may seem like a massive buff, but the fact that you would still only have four 'planets' when it comes to pop growth and building speed means you would never be able to fill them with enough buildings and pops to benefit fully from the increased space. It actually would make them less useful for a min/max setup since 16 habitats would cost almost half or a quarter the alloys depending, and give the same number of building slots which is frankly where all the usefulness/flavor/strength of a planet comes from anyway. And those 16 habitats would massively increase your pop growth to unheard of levels.
This buff/mostly nerf would make a ringworld truly feel like the crowning achievement of your empire and make it an envy of the galaxy. It should feel like the greatest accomplishment of your empire, not oh lets go build another. It needs to absolutely drain your wealth but at the same time feel as big as it really is. If we were being accurate a ringworld would have roughly 48 million districts if Earth was a 16 district planet. We obviously cant do that in game but we could make them feel far larger which is their entire point. By the time I build a ringworld I have about 3 ecumenopoli that are decently full with feeder worlds and there is no reason to have a ringworld at that point(also true since ecumenopoli are far stronger in the building category). Those 3 ecumenopoli house more people and give more jobs so why don't I just build another instead of a ringworld?
Keeping the same build time for the ringworld would help it stay relevant and the alloy cost and pop growth speed would be the biggest thing keeping it from getting out of control. Lets face it, building slots aren't whats going to make a ringworld strong its the number of pops on them. Pops are king in 2.2 and the more breeding grounds you have the better. So keeping ringworlds this small isn't keeping them balanced, its making them boring. Cause right now any other option is better for housing and I should never feel like an ecumenopoli is a better option than a ringworld section for housing/jobs.
My main complaint is the building slot/planet size ratio is off making them less useful and if I really got what I wanted the fact that they are too cheap and small.
To sum up changes:
100 districts/section
64 building slots/section
2-3 times ringworld section cost (possibly site and frame too)
Increase influence cost too (this is the greatest achievement your empire will ever do)
Fun
