I'm sure there's potential to make this tumble system very rich - my ideas after spitballing:
Ability
Dex - Starting at 15, the ability dexterity, every 10 points (so 25, 35, 45 etc) should add to the tumble cap and reduce the cooldown by -1
Skills
Tumble 1, 5, 10, 20, 30, 40, 50 add to the...