I own both consoles and can therefore say I have no sense of bias towards either side, so I'll go with Wii U. Majora's Mask in HD would be spectacular.

I want it on the same platform as Ocarina of Time since they are kind of a "set." So 3DS for me. If Majora's Mask got an HD Wii U release, I'd want Ocarina of Time to get one too.

I very picky with remakes on the Wii U. I love Zelda: The Wind Waker HD. I aslo would like to see Super Mario 64 HD on Wii U. Zelda: Majora's Mask can go to the 3DS.

I would've liked it to be on WiiU, if Ocarina of Time was also on WiiU. I find it more important that these two come together on the same system because they're a set, so now I'd want it on 3DS.

Majora's Mask would not help sell WiiU.
The more anticipated Wind Waker will have pushed like 1.5 million units by the end of the year, the best they could expect MM to do, as a rehash of a relatively poorly selling game, and as the second Zelda game on the WiiU, competing in a similar window with the new Zelda U, is half of that in sales. I don't know why they'd bother for 700K in sales over a couple years. They could at least hit 2 million on 3DS.

Remaking MM in HD would take a lot more resources than in 3D, considering they could re-use Ocarina's. The probably 9 months of work would barely be worth it.

As it stands I don't even know if I want a remake of Majora's Mask. Three Zelda remakes in almost as few years at the same time as new releases? Along with SF64 and DKCR's port and Pokemon remakes, etc.? I guess GBA and DS technically had a lot of remakes as well,  but maybe this is overkill.

I didn't buy the OoT remake, I got WW for free in bundle, and the only reason I'd buy MM again for more than $15 was if they included great quality Master Quest style content, which would again take more resources. Then I might pay $25. MM with better polys and textures isn't the place my money needs to go in this market.

I don't know if it's just me and my opinion on all this remaking and rehashing, but I feel like the general public would be more confused and disdainful than appreciative of endless remaking.

To be brief, I don't really want it, I don't think it's the best use of resources, and I'd rather it not clutter the market at the same time as two other Zelda remakes, two other new games, and a group of other remakes and remixes from Nintendo we are being presented with.

I'd rather they bring OoT and MM to WiiU VC and let me play them on my gamepad.

Makes sense for the 3DS this fall or next year as the 3DS release list is pretty thin.

Wii U will probably HD remakes of either the Mario Galaxy games or Twilight Princess later on (2015?).

Hopefully 3DS, mostly because I don`t have a WiiU..

3DS
OoT was on 3DS. Wii U's got WWHD, new Zelda, plus that other Hyrule game.

Majora´s Mask 3d is their winning card. They know you would buy a system to play it, so, why would they launch it on 3DS that almost everyone has one by now?
My bet is they will launch it to their next handheld. So don´t expect Majora´s Mask anytime now.