It could quite literally be almost any franchise. Just about every Nintendo franchise has fans that would be really happy if they announced X sequel.

Having said that: It's going to be Advance Wars.  I just know it!  He's talking to me and me only!

Vitality Sensor is coming back baby!

That's about as likely as your 200M LTD prediction! (joking)

Fiscal Years start on the first day of April and end on the last day of March

Eternal Darkness 2, s'il vous plaît. A Breath of the Wild expansion or a completely new game with Zelda as the controllable character would also make this one fan go super-crazy. As for the online focused game, I really have no idea what it could be, but I hope for a new IP.

Zelda being a controllable character is such a great idea, it's a shame that it gets mocked so often. 

I didn't actually know that the idea gets mocked so that's a shame, really. Legend of Zelda as a franchise is in my opinion big enough for a spin-off series featuring Zelda as the main character. She has evolved far beyond the damsel in distress and plays a rather big role in several of the modern entries, and so I think it would be interesting with a Zelda game from her perspective. And if a whole new title is too much there's always the DLC route. While I don't think Nintendo would do it, I think a HD release of Skyward Sword could potentially be expanded with a new side-adventure where you get to play through Zelda's parts of the story.

That was not that terrible.

my bet is on Mother 3. Nintendo has known for a long time now that western and European audiences want an official translation for Mother 3, referencing it even as recent as last year.

The Metroid Reboot decline might have more to do with Nvidia's stock value going down by I believe 16% in the same period.