I too have played since 1. I gotta say, each game has had its own "Something Special" thing(s) about it. For me, none of them are better/worse than any other. They all brought something great to the table and Sims 4 is no exception. When I go back and play 1, 2 or 3 I miss things about 4 like drag and drop building options, push and pull CAS options, multitasking, emotions and the aesthetics of Sims 4. I know that part, the aesthetics, is controversial as some think it doesn't look good but I love the art style of Sims 4 personally and miss it when I'm playing the others.
I think Sims 2 is still my favorite of the games, but catch me on a different day/different mood and it'll probably be a different answer :D