oldschool: Yeah, this franchise is EA cash cow. I wanted to like the original Sims, but it wouldn't let me be a serial-killer hehe. If you're going to simulate life, well, simulate it :P
They keep releasing the same things as expansions. All 3 editions so far had vacation-based expansion, university-based, expansion, night life - based expansion, pets-based expansion and so on...
... they intentionally do not merge previously created features... for example, pets introduced in Sims 1 through expansion, into the base Sims 3 / Sims 3 game in order to reintroduce them and sell more copies. :(