This is an academic concern, since I don't particularly enjoy the genre. Still, the advantages of the Wii U controller with regards to RPGs are pretty obvious, even putting aside any potential innovations.
Maps and Inventory. They aren't sexy, but they are pretty useful, and having a persistent inventory would be very handy, particularly in a Borderlands/Diablo-type of game. But other parts of the game, like the battle system, could also be simplified and streamlined. Want to use a potion in the middle of battle? Tap the icon. Want to issue real-time orders to your party members? Tap the icon. Want to cast a spell without going though menus and submenus. Why, tap the icon!
Imagine playing a lightning-fast RPG that isn't overly simplified. Having a secondary display would allow that. And, of course, for the grindfests, you could play remotely on the screen. (I would question why you're still even playing at that point, but whatever.)
I'm going to answer my own question by cutting most WRPGs out of the equation (at least until the PS4/720 launch), since Western companies seem to focus on the most powerful hardware. But I think there's a good chance that 'big' JRPGs could migrate to the platform. Or should migrate. Then again, I think the Wiimote offered some cool enhancements to the RPG, like pointer-based NPC interaction, but that hasn't gone very far.
@Mr_Mustache Dragon Quest V and VI came out on the Super Famicom, but Enix's North American branch I believe had closed during the time those were released, so they never came out here in America, until the DS remakes were made.
@Guillaume Yeah, I recall it getting first place in a poll for Japanese gamers' favorite games of all time. Was it Famitsu that did that?
To be honest, I'm not sure if I want JRPGs to move back to consoles en masse. I'm playing Xenoblade and making good progress, and its accessibility (easy and quick to save or load anywhere, little penalty for death, quick and dirty sidequests) have a lot to do with that. But I'd be even further in the game if it had been portable, if I could grind away while on the bus, or even at work.
Even as I'm typing this, I realize that I probably wouldn't want to lose the game's magnificent, open environments in favor of portability. And I don't mean to troll those who have a vast preference for consoles vs handhelds. But I think back to Dragon Quest IX and just how quickly I sank 100 hours in that game without even noticing.
I don't come close to 100 hours for any console game this gen. But DQIX, I did it and it really didn't feel like it.