But seriously, what class aspect didn't you like?
The use of them at all! It took the focus away from what, for me at least Simcity was always about, city building. I didn't want or need to have to play a social structure sim.
I want to build, not manage social inequalities. Maybe it's just me, but that's what i hated about it. Cities XL follows the same path, which is why i still have 3000 Unlimited installed. Yes, it's dated, and it shows, but at least i can retain the ability to ignore everything else and just build!
If 5 retains the same social structure elements that 4 has, then Simcity will be dead to me.