Truly, an endurance bar is basically built-in waiting. Would you LIKE to have to wait for several seconds every now and then? You already get that if you're getting beat down; you can just watch yourself tumble end-over-end (it's very restful).
I am whole-heartedly against an endurance bar as you've described it.
If you get tired from attacking too much... that's taken care of by the ki bar (you can't attack continuously, you have to wait and recharge). If you get tired from being beaten up... that's the stun they've implemented so well. (I'd just like to say that using ki to recover from the tumble is brilliant; you can actually exert some control over the fall, but only if you've had the forsight to keep some spare ki handy. Kudos to the designer of that detail!)
These seem to be the only effects of the endurance bar you've described so it doesn't need to exist.
The only thing I think melee needs is some variety: maybe a few more options for things to do at the end of the swoop?
They could have a "grapple" choice: if just the swoop target is using it, they can catch an incoming swooper and throw them into a tumble and if the swooper is using it they get an animated series of blurred hits (does more damage than a swoop) before hitting the target into a tumble. If both are using grapple they enter a physical power stuggle (suggested many times before) a la the cell saga with Goku.
I suppose the balance would be that grappling can be countered as well as blocked.
Swooping will take a while to really master, and it's been implemented really well, but the blurred exchange of melee blows is still missing from the game. I don't think it can be controlled on a blow-by-blow basis, but I do think it should be in there.
Sorry for the long post,
Thanks for reading
