Hmmmm, well, the blades are certainly a interesting.... No, no that wouldn't work, would it? You might as well let the player choose their Bankai and their swords 'True Form', Perhaps one skill... What do you call the areas where you put points into? Nodes? Point Nodes? eh, that'll do.
Anyway, this
Point Node Could be called something like Attunement, it would basically allow you to more easily tap into your blades power and more easily converse with your blade?
Also, there isn't much customization potential after character creation there, can't really get your blade upgraded, not following the original basis of bleach, anyway, can you upgrade your sword?
What else... What else...
So how would I go about making this workable/fun?
Add more stats, or some such?
Well, just figure out how it should play out, not how it plays out in the show. It's generally better to make the system inaccurate and fun than accurate but boring to play or rife with problems.
For specifics, I probably would go for the "more stats" approach, if only because you want ways for the players to be different from each other. Having one all-important Power stat, among its other issues, doesn't really cover that beyond "this guy's better." You could also try going for specializations or traits or something, but those tend to be a bit wonkier to pull off.
As well as being wonkier to pull off, I, myself can't really think of any skills I would be able to logically apply to a Bleach forum game... Are there even that many?
But yhea, with the best part of that idea being the swords turning into better swords, I would suggest just taking... Hmmmm.
I'm just not sure, it seems even the theoretical supports are a bit wonky here, and there's not that much to say about it.