Evans averaged 7.5 rebounds two years ago in 23.2 minutes.
The only thing Evans can do is rebound. I don't think it's fair to criticize Kapono's one skill -- amazingly efficient three point shooting -- and then harp on Evans one talent. Evans is terrible offensively, is terrible defensively, and is terrible passing. He rebounds. That's it.
Why this makes Philly much better is because they desperately lacked shooting last season. Additionally, Evans wasn't looking at many minutes next season, with Dalembert, Brand, and Speights locking up the top three spots in the big man rotation.
From my perspective, they replaced a one-dimensional player who wouldn't help them with a one-dimensional player who fills their major team weakness. Any time you replace a guy at the end of your bench with a key rotation player, I think it is going to substantially improve your team.