I completely understand your concerns, really do.
There are effects of air or ground pollution on the residential area, same goes for traffic or not enough commercial around. I guess, considering I played SC2000 as the last one, the effects aren't as drastic as they used to be. Which seems to be connected to the regions they introduced.
You could make a complete city consisting of 80% industry and it would probably still work cuz workers you lack start to commute in from other cities around you. Or the other way around - you build a city with 80% residential and commercial with a lack of industrial, therefore working places, and people start to commute to industry outside of your city.
Concerning the money management... yea, they are pretty rich and it's something that unsettles me too, tbh. On the other hand, the players in those streams are people who worked on the game/QA people who know the game inside out already. Maybe they even cheated their starting money for demonstration purposes... I dunno
...but it just looks so nice and seems to play really smooth and I really like the regional/global influence on cities. I think that it's less micro but more macro now.
I am not trying to convince anyone. Don't think I can. Merely saying that I am digging what they showed in detail in those streams.