I'd go with:
-One Piece Pirate Warriors 3: All-around well-done game that follows the OP storyline up through the Doflamingo story. The game came out before that finished, so it has its own original ending. Play mechanics are solid.
-Samurai Warriors 4-II or Empires: You know what to expect here since you played SW4 as I recall. Refined versions of that game.
-Hyrule Warriors: Also all-around well-done with some nice boss battles and some play mechanics from the Zelda games added in. You get multiple subweapons to use in addition to your main weapons. Has framerate issues compared to the PS4 games mentioned above, but nothing that stops it from being playable.
Also Dragon Quest Heroes II but you got that already.
Hyrule Warriors Legends on 3DS has some new content over the Wii U version. If you're playing it on a New 3DS or New 3DS XL, it will run nicely given the platform, but it will have a lot more framerate issues on a regular 3DS. Koei was supporting this pretty regularly and the last DLC pack just came out this past Monday.
The 3DS version got a number of new characters added. Some are part of paid DLC packs. There's Linkle (female Link), Toon Link, Tetra, King Daphnes, Skull Kid, Ravio, Yuga, Toon Zelda, Medli, and Marin, plus new weapons for various characters in these packs (that change their playstyles), in addition to new maps for the Adventure mode. It's a pretty sizable amount of extra content, although you will have to pay extra to get it all. You can pay extra on top of that to get these characters for use in the Wii U version, but I'm not sure if they get the Adventure Mode maps or not. Note that all these DLC characters do not have storylines of their own -Except for Linkle in the 3DS version- and are for use in the other modes. Adventure Mode is a big thing though and you can spend a shitload of hours playing that mode alone.
I haven't touched the game on Wii U since it came out on 3DS. There's also more DLC packs that are on the Wii U version, adding Epona, adult Midna, Tingle, Young Link, extra challenge modes, outfits, and more weapons into the game. IIRC the Wii U DLC packs are already in the 3DS version.
The 3DS version also lets you play as multiple characters on maps, just like how Samurai Warriors Chronicles plays and adds faeries. I forget what they do at the moment though, lol. They also increased level caps, but this may be on Wii U as well.
I would not be surprised in the slightest if the Switch gets an updated version of this game with all the DLC added in. Would bank on it, in fact.