There's plenty of those:
· Fragile Dreams: Farewell Ruins of the Moon. Now don't take me wrong, the controls of this game are beyond terrible at times. They either don't respond, or don't behave like they should. It would have definitively play miles better with a standard controller. This being said, this game is a brilliant apocaliptic tale, that actually moved me and made me sob at times. As a sucker for survival horror games, this one nail the atmosphere, the feeling of loneliness and has some really powerful sequences. I actually regret never beating this game, but I didn't own it so I could only play it under certain circumstances. Seriously, go play it, it's freaking amazing if you can endure the controls.
· Disaster: Day of Crisis. (Sorry americans, this never released there); IMO the best Monolith Software game despite being universally panned by critics. Why, you might ask? Because this game is lengthy, fun, has some cheesy but great storyline, a nice soundtrack, some damn memorable sequences (some other really absurds, like running away from a tsunami but C'MON DON'T TELL ME THAT DOESN'T SOUND AWESOME) and plenty of replayability. It also rips-off Metal Gear to no end on the second half and IMO that is a good thing, because it gets weird as heck. Fantastic game that I can't honestly understand why would anyone dislike it. Besides, it feels kinda unique since singleplayer survival games are truly scarce, and this one hits some good notes here and there with the theme.
· Dead Rising: Chop till you drop. Not sure if this one is overlooked, but I'm pretty sure it didn't move millions like the 360 version. Anyway, I don't really consider this game the same as the version it supposedly comes from, because it suffers from a massive downgrade in every-single area, story (no alternative endings), gameplay (completely different) and some missing content. Why is it here, though? Because oddly enough, the wii version is addictive. The motion controls add an strange layer of fun, and the sidequests that you get once you've beaten the game are very fun to play and master (something the 360 version actually lacks). If you enjoyed RE4 on the Wii, you'll love DR Chop till you drop, since the control scheme is the very same.
· Silent Hill: Shattered Memories. Very few times videogames have managed to surprise me on the narrative department. I'll simply say this is one of those few games, and despite a poor gameplay system (that boils down to a running simulator, really), the script was simply brilliant.
· Basically all Trauma games that released on Wii. New Blood was fascinating, go for that one if you can only play one!
· Ivy the Kiwi. Fun platformer, with a nice touch of challenging design.
I'll post more if I can think of more overlooked gems.