I agree (mostly) with George. Shortening the blade further would be a mistake, from the preservation aspect and the financial one as well. If the sword is not to be polished there is no reason I can think of not to leave it as is, in the koshirae. If it is to be polished then it goes to shira-saya and a tsunagi holds the koshirae together.
The one alteration I would consider, and I'm not sure if this would be advisable or even possible, is to have the nakago bent backwards to reestablish the concave curvature on the nakago mune. It seems that this might give the nakago a more conventional sugata (the reverse curvature of the present nakago bothers me) and it wouldn't require the removal of steel.
But, as I said, I don't know if this should be done. Can we have some other opinions? Ted, what would a polisher do about this?
Grey