In TS2 they had an expansion pack devoted to apartment life. In this pack, it allowed up to 4 families to live in the same apartment building. You could go to their apartment, similar to how you go to another sims house now, and you could hang out with your neighbors on the weekends. It was pretty cool. When TS3 came out I expected to do some of the things I was able to do in TS2. So when the apartments came out in night life I expected them to be on the same level as TS2 apartments or better.
That is why alot of people are disappointed in my opinion. They expected TS3 to have everything TS2 had and more. When I think they are bringing out a new version of a game I think of, better, more things to do, and all the great things to be carried over from the last and improved. That is just my opinion though.
So I understand why people were disappointed with the apartments.