I actually have nothing against City per se. I'm not from Manchester myself, so the local rivalry thing isn't really relevant to me. They can spend what they like, it's never really bothered me with City or Chelsea (apart from the whole sugar daddy thing, but that's another argument) since it's up to us to meet the challenge. I have a certain hatred for Liverpool for other reasons. The whole 20/18 thing, the Suarez affair, the fact that most of their fans and players genuinely seem to live in this delusion coated bubble. I could go on. But i don't really feel much towards City, not yet at least. I don't even hate your players that much. Toure does a huge amount for Charity, Milner seems a good laugh, and apart from the odd meltdown and arrogant media sound bite, Kompany has always come across as a decent guy too.
I was born in '93, so maybe i'm too young to remember the club you were long before the takeover. But from my perspective, and i'm sure the perspective of many other young fans, it's a little on the meh side right now. The longer you're successful the easier it will be however, as you say. If you go on to dominate the next 20 years as United dominated the last, then City will be one of the most hated clubs around. It's just jealousy, pure and simple. But other league winners such as Dortmund and Atletico are afforded a more instant respect due to their underdog status and how the club is run. If you pour a billion into a team, you almost expect them to win it.