what kills your theory is that generally when the 'second' Zelda outting on a console failed it was a rehash/release. AKA Twilight Princess on the Gamecube was squeezed onto the Gamecube but clearly primarily destined for the Wii at that point, Wind Waker HD is a remake, Ocarina of Time 3D (3DS) remake, etc. etc. etc.
no mainline Zelda game on console has ever faired particularly poorly next to another Zelda game, except for Majora's Mask (which was just a massive departure from Ocarina).
Zelda Wii U will do awesome. there is massive anticipation for the next home console Zelda game, especially after Skyward Sword was such a departure in terms of certain traditional things (art / style).
The real question I would ask at this point is not whether the game will sell well (it will), but whether or not it will in fact be released on the Wii U OR the next Nintendo system
if the game were to release both on the NX and Wii U at the same time then arguably the title would no longer really be a priority Wii U one nor would it be 'Zelda Wii U'.
if it exclusively comes out on the Wii U it will probably have something crazy like a 40% attach rate
