Okay don't even start on only the flaws. It isn't an opinion that Xenoblade is more usually impressive than Tropical Freeze. Some might prefer the artstyle in Tropical Freeze over Xenoblade, but it isn't more visually impressive. In any way. 

Do you have any evidence for that? Maybe 500k people have bought a Wii U for DK, but only 400k one for Splatoon?

Xenoblade Chronicles X is an excellent game but Donkey Kong Country Tropical Freeze, also an excellent game, sold more copies than XCX. And Splatoon was bundled with the Wii U an DKC TF wasn't so that's more merit for Retro who sold a decent quantity of games being a non-bundled game, And the first DKC was a system seller, believe me, I was in that time when the 9 million plus sold copies of DKC saw a rising in sales for the SNES against the Genesis.

I think Japan going bananas over Splatoon says enough for this.

It means nothing, really. GameFreak was also a garage team when they made the original Pokemon, and it duplicated the sales of the GameBoy. Surprise hits are really hard to produce, so Nintendo still needs studios that produce quality games and moderate successes.

Splatoon sold 4x as much and caused a sorta significant bump in Wii U sales whereas DKCTF did barely anything. You can look at the charts and see for yourself. Splatoon is also bundled, DKCTF never was to my knowledge. 

It means retro is doomed.

Well, I can´t say no to that reasoning but I wouldn´t underestimate Retro, I´m sure they work as hard as they can and they believe in what they´re doing. I know they are capable to do great things, DKTF is such an amazing game! It truly is, but people didn´t think the same, or there wasn´t too "new" to buy it.

I think Splatoon has sold that great because it is new in almost every aspect of the game, fresh gameplay, nice visuals, adorable characters, nice difficulty for everyone (while DK is always hard, at least for me, I still can´t believe the freaking giant octopus killed me like 40 times in a row xD) and so on.

Splatoon is a beast, and I really hope it keeps selling even better once Splatoon 2 is released, as it deserves it, but I still think there is enough place for a new DK in the future (though obviously, there should be a new Metroid first :P).

If people is not impressed by those cars, let alone by DK's fur.

I don't think it needs to be a Metroid. It only needs to be something impressive that push the next console to its limits. Something that we expected and know Retro can do.

"Guys look how relevant splatoon is!" Every nintendo fan on vgchartz, haha
Ps: I think its a great game