Board Thread:General Discussion/@comment-26475399-20151228215405/@comment-26091912-20151229083244

Yeah, the problem with this theory is it overlooks the fact that Final Getsuga Tenshou is a Zanpakuto technique.The only way to achieve the Final Getsuga Tenshou was to accept Zangetsu's blade, which Ichigo inherited from his inner Hollow; nothing to do with Quincy techniques. 'Old Man Zangetsu' always used Ichigo's Hollow powers when learning the intricacies of his Zanpakuto.

Not that any of this matters, because Final Getsuga Tenshou was a contrived plot device in order to counteract another contrived plot device (Aizen's evolution via Hogyoku).