Oh great and powerful dev's just a request, and yes I know it deviates from PNP rules.
Due to the mechanics of this game as it stands tumble pretty useless (but still cool looking).
If you get surrounded by mobs your your supposed to tumble around to get your +4 to ac at which point you cant attack? You can't tumble through them to safety. So your just sitting there rolling around.
So why not make mobility work when moving at all. +4 to ac while in motion.
You get a cool dodge bonus... then you get +4 to ac while moving... then you loose your attack penalty while in motion.
That way it works for the play style that spring attack generates. Running around swiping at things.
My $.02