This is a very likely candidate really. DK is a big franchise for them since the revival and the game suffered due being on the Wii U. So Nintendo upping the game and selling in the future could certainly happen.

I would definitedly want to see Mario Maker on the Switch, but I have a feeling that if they do it, it will be more like Splatoon ("Mario Maker 2") with more features, different online setting, etc.

I missed Paper Mario on Wii U but I doubt it will come to the Switch. Same for Xenoblade Chronicles X.

Other titles are more likely to get a sequel other than a port: Paper Mario, Star Fox (porting should be hard due to second screen need), Donkey Kong.

Smash Bros. could see a port with all the DLCs - but I bet good money there will also be a sequel - it depends how it would fit to Nintendo's plan to spread big releases.

If they keep porting more NES/SNES/N64/GC/Wii games to 3DS/Wii U/Switch, I will Boycott Nintendo forever. This is essentially what you are saying.
Oh but I am sure that you are fine that they ported a bunch of Wii games to the Wii U, right? Or even GameCube games being ported to the Wii (Pikmin, Metroid etc.).

Nintendo is not taking these games away from you, you still get to play them on the Wii U. A business giving new life to their games isn't exactly new. 
The PS4's backlash to remasters such as The Last of Us and Uncharted (as well as other titles) were bad enough with people complaining that the PS4 was just a remaster system. Some Wii U owners on the other hand are on a whole new level. They literally complain over nothing. 

Nintendo is far more successful with the Switch. Do you think they, or anyone else cares that you and a few others are emotional over nothing? Highly doubtful.

You know, with the recent announcement of Samus Returns and Reggie focusing on making games seem fresh, it gets my hopes up for a Mother 3 remaster/reimagining. I get excited about the possiblities, and then I realize it's Nintendo, and they purposely get my hopes up for great things they announce, but they're just not the things I think will happen.

Nintendo, Y U DO DIS?!

as a massive Nintendo fan that got the 3DS but skipped the Wii U almost entirely- I hope they do this. Although honestly I don't think there are THAT many awesome games that I'd want them to port.

Specifically though- Mario Maker pleaseee. Either a port or a new version.

Xenoblade X would be cool. Bayonetta 2. Tropical Freeze.

Probably Mario Maker and Trop Freeze are the most logical and the ones I'd be most excited to play.

as far as something like Smash is concerned- I'd much prefer a new version comes out rather than an enhanced port. As far as the 2D Wii U Mario game, and Mario 3D World- I'm not a huge fan of either so indifferent about them getting ported, and in fact I might suggest they DON'T do that as Odyssey is already coming out. Obvs no Metroid or F Zero title on the Wii U too worry about. no Pokemon game really (Pokken ehhh).

uhhh they will never do that because they know they could get like $40 individually for each of those if they port them seperately, maybe $60 in some cases (Pikmin 3 / Wonderful 101 probably not full price)

yeah wait 5 years, 10 years, 20 years, you'll be dead at some point. That is possibly the worst logic I've ever heard. 

how is screwing them over? Nintendo spent money, time effort- to develop the Wii U and games for the Wii U. Unfortunately not a ton of people bought them and the system was generally a failure. Nintendo didn't force anyone to buy their product, and there certainly isn't a clause or contract that they're permanently stuck to the platform

they stuck around a lot stronger than Sony did with the Vita.

You're being kind of petty- I mean it's fine if you don't want to get a Switch or Nintendo product. Fair enough. but to imply that Nintendo is 'screwing' Wii U owners be rereleasing games that did relatively poorly on the Wii U because there was a very small install base? that's absurd. You realize Nintendo is a business and they invest to make these games right? Logically if you like the games or like the developer you should want them to get SALES. and you should want more people to experience a series you dig.

No one who currently owns a Wii U is forced to buy a Switch and rebuy the same games again. And debatably, conceptually, the Switch and Wii U are fairly far apart. One being part portable system, the other entirely for home. if after year 3 of the Wii U Nintendo had popped up quickly with a new system and abandoned you guys and launched a new console with a bunch of ports- that'd be screwed up. But that's not what they did at all. They waited 5 years and for most of that period supported the system. Get over it.

porting potentially can give life to the installments/series that did poorly on the Wii U, pays back development costs, and fills in library schedule release holes. 

If we reach a point where Nintendo is just throwing out ports and not bringing new stuff- then I'm all for shitting on them even harder. But Zelda was new for both consoles simultaneously- and Splatoon 2, Arms, Mario Odyssey- we're seeing at least some effort from Nintendo to bring new stuff

I feel like it wouldn't be worth it for them to port NSMBU...

If the Seitfh continues to see the kind of success it's had so far (and probably even if it doesn't), a new 2D Mario is inevitable...

Having a port and a new title would result in brand confusion, which after the incredibly weak branding of the Wii U, they need to avoid...

Bayonetta 2
The Wonderful 101
Xenoblade Chronicles X
Tokyo Mirage Sessions #FE-best Persona game on a Nintendo system.(note didn't sau best SMT just best Persona game on a Nintendo console)

All those need to happen on Switch.