Been playing Sims 4 for a couple days now....
There are some GREAT things about it. I love the new graphics (I know some hate it). What's really awesome is Sims can multitask. They can eat and watch TV, meaning you can take care of multiple needs at once easily. The social interactions ARE more dynamic. They naturally fall into 'group conversations', Sims will actually change what they're doing in order to interact with other Sims (ie if they're eating in the dining room and realize someone is cooking in the kitchen they'll get and up and join the other sim in the kitchen. If someone's watching TV they'll take their meal into the living room to interact with the other sim, watch TV AND eat). Careers aren't so easy to just get a promotion in, there's 'daily tasks' as well as skill levels and other goals to meet. It isn't so easy for kids to do well in school either. Seeing the sims' reaction to emotions is kind of fun too. I haven't gotten a kid raised to teen yet, but we'll see.
I'm still getting used to building houses (little difficult to do with a touch pad on a laptop). I can't say it's 'dynamic' but I like that you can drop pre-designed rooms into a lot without having to fill it with furniture yourself. Everything feels a little more 'real' as well.
On the other hand...like any base game things feel more limited after multiple expansions in the previous iteration. Fewer choices for hair, clothing, decorations, etc. I especially miss seasons, I really wish they had built those in.
I don't really care about pools, and honestly the toddler stage in Sims 3 was just tiring for the parents and a pain the get the toddler through all the developmental goals (walking, talking, potty training). Odd that they eliminated dishwashers, but oh well.
Open world vs. Closed world: Open world was more realistic obviously, but I always felt there was so much time wasted watching in Sims 3 watching sims run, bike, drive, boat between locations that closed world feels like less of a time suck. Loading screens are annoying though. Hopefully with expansion packs there will be more options for more 'worlds' with more public locations and more prebuilt and open lots.
Anyway, I'm enjoying it but it feels like it's lacking after the completeness of Sims 3 with expansions. It has potential to be great fun.