I thought we already knew this, or at least that Twilight Princess started out as a Wind Waker sequel. The horse part I don't think I heard before. I agree that would have been weird to have in WW style. Anyway since Twilight Princess is better, and sold way more (and a WW2 on GC would have sold even less than the original WW as well probably), the right decision was made. Besides, WW actually did end up getting a sequel; Phantom Hourglass, I don't see why they'd forget that one.
As a sidenote I do want that book, february it is then. 