What if, Bloodlust was removed altogether, since there's already plenty of moves to regain attack bar..
And Oak stance was changed:
The rate at which you replenish defense bar from attack bar, on opponent's moves is inversed to the current situation:
So, instead of gaining huge benefits from battling a inferior foe (/alt), you will get better defense regain when battling a more powerful foe than you.
It kinda fits with the Oak Stance IMO. If you look at for instance win chun kungfu, one of the basic ideas behind that is to 'stand like a tree'. I think win chun even literally translates to tree stance.
This enables smaller, less strong warriors trained in this way, to be able to defeat foes much stronger and bigger than themselves. Sorry, realism argument

As for how it would affect the game, I think it would solve the OP's problem with using noob alts.
It might also just give somewhat lower level characters a chance to beat a higher level character, with cunning use of techniques, which I think adds to the gameplay value. More influence of player skill vs character skills is not a bad thing.
The stronger character would still keep the advantage of his higher skills though I do think, as it should, but to a somewhat lesser extent as it is now.