The expansions that let you get out of the house (Hot Date, Vacation, and... uh, the one with pets) are considerably more resource-intensive than the original. These ones add (marginally) to the scope of the game. Otherwise, the expansions just add more stuff (right off the bat), but it's still the same damn game that came out in, uh, February 2000.
I feel a good deal of guilt and shame over my (repeated!) purchases of Sims expansion packs. I keep hoping they'll bring back the magic of the first week of gameplay, but no, it still seems like some horrible God-awful tedious chore every time I decide to install it.