Caved and purchased a Wii u, comes with 5 games, new smb, Mario maker, rayman, mass effect 3 and sonic racing.
I know what other games I'll be getting - 3d world, Mario kart 8, ssb etc...but what hidden gems are there?
I got it primarily for Mario maker, some level designs I've seen on twitch/yt look amazing
If you like local multiplayer and have extra Wiimote controllers for it, picking up
Nintendo Land on the cheap is a good shout. It's impossible to get bored of the Luigi's mansion game, I swear.
I bought my WiiU for
Monster Hunter 3 Ultimate. Pretty much the only Monster Hunter released on a reasonable platform in recent years, since the others have released on the terrible 3DS (I have them and MH3U is still my favourite). If you like Dark Souls and/or Bloodborne type of games, you'll love Monster Hunter. It's mainly a boss rush with some deep mechanics and a strong learning curve. Anyone who says WiiU only has easy/child-friendly games has never played Monster Hunter. The online co-op multiplayer might still be kicking, I've not checked. I know it was still strong a year or 2 after release. It's my most played WiiU game at 400+ hours (though 100 of that was on the 3DS due to amazing cross-platform functionality).
On that note, I don't have it but I hear
Bayonetta is similarly good, for a more 'grown-up' game on WiiU.
If you like strategy, then get
Pikmin 3. If you have OCD and don't want to let a single Pikmin die, then don't get it. You'll never get around to finishing the game lol. I know I've not played it much for that silly reason.
Related to that, the WiiU can still play Wii games, so get
Battalion Wars 2. It's a very underrated strategy game, with plenty of charm and has similarity to Advance Wars. Except it's real time and you can control any individual unit. Battalion Wars 3 would have been awesome on the WiiU, the gamepad would have been perfect for it. Alas it never came to be. Similarly you can also get
Metroid Prime Trilogy. You can even just download it from the eShop for fairly cheap. Among the best and most atmospheric single player fps out there, there's really nothing like it.
One of the few WiiU games I've completed is
Legend of Zelda Wind Waker HD. My word that game is amazing. Even visually it puts the later released Twilight Princess HD to shame. The best Zelda experience currently on the WiiU.
And finally, the one other game that comes close to Monster Hunter in the sheer number of hours I've played (320+).
Xenoblade Chronicles X. It feels like an MMO in some ways to me, but I hate MMOs so it must be doing something right. It's an amazing RPG, with a very in-depth combat system, and open-world that is literally chock full of things to do (no vast open spaces with nothing to do in this game). I loved exploring the world, doing quests, killing enemies for materials to make stuff and it kinda even has 'end-game' too. It has various QoL limitations though and the thing I hated the most about it was the story. If only because of the way it ended and how some plot aspects felt shoddy. But that's just me, I'm fairly harsh when it comes to storylines.
So there's plenty to get and play on WiiU. The only problem is finding the time for it lol.