What's to like about Hyrule Warriors? You're mashing the same buttons over and over again. There's little depth in gameplay and it looks quite bland and ugly at the same time.

Mario Kart 8 to me has the best selection of tracks. The only thing that sucks is the item balance and battle mode. Mario Kart Wii just sucked. 

Double Dash remains my favorite, but most likely because of nostalgia (it was my first Mario Kart) and it's by far the game I played most with my friends (local multiplayer will always trump anything else). It also had 60fps even when playing with four people locally. And who didn't love the 2 characters per kart and special items... The battle mode also had the most interesting modes, I loved bob-omb blast a lot. 

So:

1. Mario Kart: Double Dash

2. Mario Kart 8

3. Mario Kart Wii

I'm not sure where you live and what stores you have available to you, but most of those are pretty easy to find besides Pikmin 3.

And to comment on your FE discussion

Radiant Dawn is personally my favorite Fire Emblem game. I like Awakening, but meh. Not the best in my opinion even though I have played through it at least 10 times by now. (Played through Radiant Dawn over 50. Literally, no joke.)

2 characters per kart is nothing special, I was actually glad to see one per kart back in Wii, and the battle mode is better in 64.

About HW, I was not talking about how brilliant is, but how little it has to do to be more entertaining (to me) than MK8 and SSBU, even when the gameplay is repetitive and boring. I'm just going on for the Ganondorf scenarios.

Radiant Dawn is the one on Wii?

Mario Kart 64 is trash. Played it at my friend's house who owns an N64. Hasn't aged well at all. 

DD battle mode is far better. 

Just like the N64 courses in Mario Kart 8 are far better than the (bland) original ones. 

And Hyrule Warriors is definitely the weakest game of the 3 you listed. By a lot. In terms of sales, in terms of critic reviews and in terms of user reviews (metacritic). 

Yes, it is the one on the Wii. And I do have to say that the music in RD is way better than Awakening's. ESPECIALLY the final boss theme. I have never (well, exaggerating a bit) heard a theme on par with RD's.

I still don't get the love people have for MK64 and DD
I have both of them and I personally don't like them that much
In MK64 the tracks were really boring and the AI was pretty bad, not to mention horrid controls
Double Dash fixed the issue I had with the AI and the tracks, but the controls were almost as bad as Mk64
Idk, might be nostalgia for most people, but I think MK8 is the best one

Nope. MK64 tracks with less effects, lighting and worse graphics requieres better skills, are more narrow and more varied. MK8 just looks beautiful but doesn't have any difficult, are wide and with different ways enough to eliminate the sense of being in a competition. All you need to do is keep your distance and use items, which, are worse and you can only have one at a time (way inferior feature to the predecessors), with examples like the useless coins.

MK64 tracks are bland and ugly. The game is not as narrow because it supports 12 players now, instead of just 8. Mario Kart Wii was fucking annoying with everyone bumping into you. At least in Mario Kart 8 you get a speed boost when someone bumps into you while you're in anti-gravity mode. Very good addition, even if it's small. 

This is the same situation as Smash Bros Melee. I had never played it before until recently (couple weeks ago) and it SUCKS. It is so unbalanced, way to quick paced and etc. Seriously, sucks. Nostolgia is the only reason people say it is the best.

As for Mario Kart, I definitely agree that when ALL pros and cons are shown, Mario Kart 8 is the best.