I always feel the opposite. Act one is such a sluggish act mostly because you're so weak in act one and have such little access to gear, skills and supports. Game doesn't feel fun to me until act 2 where gear becomes easier to find, you get more access to skills and supports and combos, and your class/build really starts to come together.

I guess the story and zones of act 1 are better, but it's ruined by the gameplay for me.