After playing for the last 4 hours... I conclude it's fun.
I like the new method of weapon drops (randomly while playing, and it could be for any class, rather than being tied to achievements). Yes sometimes you get duplicate weapons, but there is a management screen for that.
Sniper and Spy is fun still, not groundbreaking changes like some of the other classes, but still upgrades.
The new Maps are fun, especially the dual-payload one, and the new arena_sawmill has a brilliant atmosphere to it -- too bad it is an arena map.