I was actually thinking along those lines. I mean his Getsuga concentrated into a piercing arrow barrage could be damaging, but I think the most important aspect would be the Quincy ability to control reishi. It might be the key to getting back the other Captain's bankais and countering the power some of the more powerful Quincies have. Not to mention, since they have shown that they can still a bankai once they know about it and/or understand it, it's probably for the best that he hasn't gotten Zangetsu fixed yet. So I guess once he learns the truth, it's likely that Uryu and his father might be able to help train him or awaken his Quincy powers.
Also I'm guessing that Ichigo's mother is the reason that Ryuken and Isshin are on decent terms considering the whole Shinigami/Quincy issue. I actually wouldn't be surprised at all if Ryuken was related to her in some way. I'm also starting to think that Isshin abandoning his powers may have had something to do with one of Urahara's special gigais so he could live peacefully with Masaki as opposed to my initial thought of it having to do with the Final Getsuga...Although it could be both.