Good Wii RPGs I've played:
Arc Rise Fantasia
Muramasa: the Demon Blade
Super Paper Mario
Bad Wii RPGs I've played:
Tales of Symphonia: Dawn of the New World.
EDIT: Zelda is not an RPG.
Yes, I'm very aware that Zelda is NOT an RPG. Some think that, and I mentioned it to help ensure no one suggests it to me. I do have Fragile Dreams, and Muramasa is on my Amazon Wish list. Arc Rise Fantasia, I'll look into it.
I really liked it. The voice acting is a bit much for the most part of the game, and the graphics are meh, but the battle system of story were top notch. I was very pleasantly surprised. Also, as someone else already mentioned, there's tons of good RPGs in the VC library.