So, we'll only ever be able to control one family?
Either that's not what you mean, or that interview thing is false...

No you can control more than one family but when you are playing a family your other families will go on with their lives when you aren't there... So you might be playing the Smith family and then go back to playing the Jones family and they have had a kid since you last played them.

Hmmmm... Idk if I like the idea of my sims having kids/getting engaged and stuff without me knowing or not.

I like having control of my sims myself. But, at least if there's two twin brothers for example the one wont grow up to an adult when the other one is still a child just because I play with one more than the other (stuff like that really bugs me with the sims 2)

That doesn't bug me too much because that is a choice I make as a player. Now it does annoy me that there isn't anyway to age child townies in TS2.

On the whole, TS3 doesn't sound all that appealing to me based on my style of play. Let's say you have a neighborhood with two dozen families and you control only one at a time. I wouldn't be able to keep track in my mind what is happening with all of the other 23 families. To me, I don't see the difference between having the computer simulate those families and just having the NPC's produced randomly.