There are alre already so many zelda remakes this gen, I doubt tantulus/nintendo decided to port another zelda game when they made the decision 2 years ago.
Here are the outcomes I see.
a) it destiny, this was a huge rated T game that would make sense porting to the wii u. Even if it wouldn't sell well, at least the wii u would have a huge third party title.
b) it's portal 2. Game that makes sense looking at the user base.
c) it's cancelled. This would make the most sense for destiny seeing as they thought the taken king and the install base wasn't enough to justify completion of the game.
even if the game is not destiny, we haven't even heard a name for this title even though they worked on it for 2 years! That leaves me to believe it's cancelled/heavily delayed
-"It’s not an MA / 18 or ‘hard core’ game which ME-3 and DX:HR are". - Destiny is hardcore shooter game.
-"It’s the biggest thing we’ve ever done. Bigger than ME-3 and DX:HR". - Portal 2 isn't bigger than those two games.
-This game is more than 2 years in development, biggest Tantalus project ever, so I dont think that game would be cancelled after so much work and resources spent.
-Destiny is not hardcore, and it's rated T, so I don't see the problem. FPS does not equal hardcore.
-Portal 2 was fairly big since launch. Likewise, the could go for a remaster, not just a stright port, that in itself would let the claim it is still their biggest project
-Games get cancelled all the time despite substantial work being put into something. Crysis 3 was near completed for the wii u but was not released for reasons. Ubisoft had a completed wii u game that did not release for certain reasons. There is nothing that prohibits tantulus from cancelling a game despite work being put into it. Likewise, there is nothing that indicates that they haven't cancelled the game. We haven't seen a trailer, we haven't seen gameplay, and we haven't even been given a name. This happened with project cars, where we had little to no info about the wii u version, and despite some wishful thinking, the game got cancelled