you're crazy, some of those opinions are extremely subjective. in terms of scores and popularity almost none of the opinions you put on those Wii U games being better than their Gamecube counterparts are correct

both sales wise and rating wise you're off 

the Wii U has some solid titles but they have a weak Mario installment (that's the reality, it's not even traditional 3D and therefore much less loved), a remake of Wind Waker (and no improving the graphics doesn't magically get tons of points, it's not a hard thing to do), and Pikmin is a totally different type of game than Splatoon so that is just a bizarre comparison. if anything it shows that the Wii U has such a limited library that you DONT have titles available to compare appropriately with even the Gamecube

the Gamecube has a great library and the only thing weak about it was sales. highly considered system in reflection by most people, it had good specs for its time, all genre of games besides maybe shooters, and a controller that made sense

obviously the Wii U is not even close to the worst system ever. Jaguar had NO library and this is coming from someone who has owned a majority of its library through time. Saturn was very one dimensional

currently I would probably compare the Wii U to the Dreamcast in terms of library, not great, not a ton of releases, its rather ehh

Mario sunshine was not the end all be all of graphics, but it did demonstrate an advancement in water physics, which is something to 3d worlds nothing. To top it off, the game had greater exploration and puzzle segments.

In terms of mario kart and the double dash feature read this:

http://www.ign.com/articles/2014/04/03/mario-kart-double-dashs-dual-racers-havent-been-forgotten

clearly they thought double riders was a cool mechanic, but surprise surprise, the wii u processing power held back that development (among other things)

Again, pikmin is a puzzle/exploration game, and splatoon is cod with cute graphics. To compare the 2 would be very hard to do. If you do want to make a comparison, compare pikmin to the other puzzle games at the time, and splatoon to other shooters of its time, and you will see how short on content splatoon really is (even with all the dlc factored in).

Wind waker and its "cartoon" style is still considered one of the best zeldas, the wii u doesn't even have a zelda game yet. Sunshine at the very least was a good attempt at a 3d mario game, the best the wii u has is the 2.5d 3d world.

The gamecube get put on a pedestal because it had the games to back it up. Don't believe me, tell me which system had the better hardware for cheaper at the time? And while your at it, please tell me which game ended up with 2 metroid primes, an f-zero game, semi-decent 3rd party, Animal crossing, 2 zelda games, luigi's mansion, and paper mario, among others

The wii u has good games, but let's not suddenly pretend that it deserves to be placed higher than past Nintendo consoles when the wii u library clearly seems to be the weakest out of all Nintendo consoles.

GameCube first party is overrated.

Mario 3D World >>> Sunshine.

Like seriously take off the nostalgia glasses with Sunshine, it's a terrible Mario game with bloated level design all set on a tropical island (who the hell thought a Mario game with all tropical themed levels was a good idea?), that had camera glitches and bugs up the wazoo and the back end of the game was piss poor.

Splatoon >>> Pikmin

These were the so-called "new IP" of the GameCube ... I'm sorry, Splatoon is way better. It's a far better game and truly the next great Nintendo IP. Not only that but Wii U has Pikmin 3 as well.

Mario Kart 8 >>> Mario Kart: Double Dash

Double Dash had a pathetic number of tracks, MK8 has far more content.

Smash U = Smash Melee

Smash Melee was the one big IP Nintendo got right on the GCN, but Smash U matches it IMO.

DKC: Tropical Freeze > DK: Jungle Beat

EAD Tokyo made a good effort here, but a "real" DKC game with actual controls the return of David Wise trumps a spin-off DK game with bongo controls.

If Zelda U is better than Wind Waker, then the Wii U has the GameCube beat in many major Nintendo IP.

lol the worst part is that they used 2 32 bit processors and called it 64 bit. There was a major difference between the Jaguar and the N64.

I don't agree that's it's "clearly" the weakest. 

IMO both the GameCube and Wii are really overrated by Nintendo fans here. 

Wii U has several key Nintendo IP that are better than the GameCube or Wii, and Splatoon is the best new Nintendo IP in probably 20 years (sit down Pikmin, there's a reason why you're a B/C-tier Nintendo IP). 

"several key Nintendo IP" - where are they? gamecube had metroid, animal crossing, 2 zeldas, 3d mario, luigi's mansion, eternal darkness, f-zero, 2 3d pokemon games, fire emblem, and more, does the wii u have those?

Splatoon is a decent new IP, but compared to animal crossing (gamecube new IP), metroid prime (gamecube spawned), wii sports (wii new IP) and xenoblade chronicles (wii new IP), calling Splatoon the "best new Nintendo IP in probably 20 years" is laughable.

Yes, I will call the wii u library the weakest out of Nintendo consoles when it is clearly missing many games and IP that the others had, no not just b/c tier games, I'm talking about metroid, animal crossing, 3d mario,...