From my old Xbox days I say then stay away from Vesperia because it's GOOD!
It was my first Tales of game and I wasn't expecting much, to my surprise, soon I got caught into it, so since you want something not too engaging, I recommend against it.
I didn't like the little I play of Lost Odyssey much, so maybe this should be the one.
A recommendation, I played a good amount of the first disc of Blue Dragon. I found it fun, easy to pick up anytime, since its mechanics are basic as they can be and the plot doesn't seem difficult to follow in the slightest. So I'd recommend it. This is a game I regret not playing more but my 360 broke and later I sold it, so too late for me, unless the next Xbox brings it back in some way.
Last Remnant I played a little on the PC. It's not bad but there's also something missing. At least this one has some new ideas but people say the 360 version is full of slowdowns (a little better if installed on the HD), so I'd keep that in mind.
One 360 RPG I wanted to play, released last year on XBLA was Dust. It looks beautiful, and reviews say it's good, so I'd at least check it up.