First of all, yeah, the atmosphere here is really negative all things considered. This isn't some big dev team with enormous budget. Yes, I'd love to see pillars too, but I don't think that this is really so game breaking that the devs should use their little resources to develop something that is purely aesthetic, especially since we can only really see it when we zoom in close. Of course negative opinions too are valid, but they should be expressed in a constructive and adult manner instead of screaming how shitty and pointless everything is. Unless of course your goal is to make sure that devs (of any game) don't get too motivated.
As for this DLC, I can see use for monorails. Judging from the screenshots it seems like these are quite similar to trams capacity wise. Trams are good feeders in dense areas, but just like busses and trolleys, they are not so great on longer routes within cities because they have to deal with all the traffic and traffic lights. Monorails however seem to have the same capacity as trams and they are elevated, so they can cover longer distances faster than the networks on the ground. Of course you could use metros for that too and if you like to build very complex metro networks that cover most of the city, then you probably won't have much use for monorails. I however like to be a bit more conservative with metros and only build them as main arteries for very long distances with lots of people, which I think is more realistic anyway. Therefore monorails can fill the need for medium distance routes and places where you don't have so many people that capacity of metros is really necessary but using trams, buses or trolleys would result in very long travel times. And of course if I'm correct and it's specs are more similar to trams than metros, then it's obviously going to cost much less to build and maintain than metros. That feature should make them especially good for early game. As a smaller network they might also be more flexible to build, but we'll see.
tl;dr: Good for medium distance routes inside cities with average amount of people, where metros are overkill and trams are too slow. I think it's a good addition which lessens the need for metro spaghetti.