I think Maxis have learned their lesson with Spore, Darkspore and Societies (I know, not Maxis but lesson still learned) on the negative side and also Sims 3 on the positive side.
My hope is they now know what we want and what works. I also think they must have been following the user base of Sim City 4 and what they've done with regard to customization. They'd be insane not to.
I have confidence SimCity V will be a return to the depth and level of customization available in SimCity 4 with the added features of an online sharing community (something that worked from Spore).
Seriously though, I am pretty excited. Hopefully this is an actual simulation, and not dumbed down for consoles. Gah, only 30% done or whatever that percent was does not make me happy, but I am nonetheless excited! I have been wanting a new sim city for years... Sim City still isn't cutting it for me as far as the performance on the game is still crummy even on a newer pc/mac (yes, I have it on both... :\ ), and Rush Hour seemed like it was "rushed" and could have used some more time in the oven.
Eh, I am not sure where I stand... I still have Sim City 3000 installed just so I can build cities listening to that soundtrack. Yeah, I remember playing that game at the tail end of my highschool career, starting in at like 10pm when I would get home from work, playing then until like 3:30am (not really by choice, just never looking at the clock again once I sat down).
I'm ultra excited that there's a new Sim City on the horizon. I'm hoping this isn't simply an obvious visual upgrade on Sim City 4 and that they've added in more features of modern cities, including mixed use residential/commercial and bike lanes.