At the moment, it's a little underwhelming to waste a feat on +3 to a skill versus other feats available. While no doubt there is a balance issue linked to tumble, could it be improved to +5 or something?
I can see an argument in buffing them a little, although I would prefer some more interesting changes, such as the skill focus: heal, than a simple increase to their bonus.
Hide and MS now seems pretty pointless to waste feats on, when stealthy gives the same amount in each skill.