I think TS2 is worth playing for the gameplay and I still like the graphics, but it is definitely much more demanding than 4. Trying to care for a household of 8 is so much harder, but so much more rewarding in my opinion. The needs are also much more difficult to maintain, but there is much more control over the world.
Some of my favorite content, pets and witches, is also better in it in my opinion. You have a lot more control over things like apartments and I think aspirations are more rewarding though also more difficult.
Basically, think deeper but harder. Fun is definitely to be had, but sometimes you want difficulty and sometimes you do not. They both have their place.