What Simcity got right was all the window dressing. Asteroids, Alien Invasions, Zombie Apocalypse were all decent. However, the basics were utterly flawed. The restrictive play size was a huge issue, and then end game goals being set so that there was no feasible way to accomplish them. It was impossible to get the max population needed for all the unlockables, and have a functioning city. Most of that could be tracked back to the over restrictive play field that forced you to build way too close to make functional traffic. When a real city has to do that they have other tools to make it work that were missing. One way streets would have made a big dent in how things function. You can't make a functional interchange without one way roads. It's not possible. You'll just create a traffic jam if you do. The most annoying bug in Simcity was how much a failure the bus system was. I had perfectly functioning cities that went to mass unemployment after adding a bus system. The buses failed to get people to work on time so consistently that they'd lose their job, then their home, and then I'm swimming in homeless. Remove the bus system and the problem slowly fixed itself. How does a real city address this problem? Buses have routes that go from A to B. Hit a central Hub so the rider can go from B to C. Skyline has bus routes, and though I'm still fiddling with it to figure out how to make it work well it's head and shoulders above dropping down bus stops in hopes that the busses don't pick people up and go in a loop around the block 5 times because 1 person wen't to the previous bus stop so it has to turn around and pick them up. They missed the bus, and can get the next one unless you have no routing system, and you're going with the closest bus stop with people algorithm.
For having a vastly inferior collection of window dressing. (I kinda miss the zombie attacks). Lack of a Day Night Cycle(days just go by too fast). The base game of Skylines is rock solid. I'm sure the modders will put some of the stuff I miss back in. In the mean time I'm just having fun making a functional Highway network.
I do miss some of the research unlockables too. Getting unlockables by simply having a large enough population seems unforfilling. I liked having to research the advanced tech at the university.