Devas works for them. Old-school devas were just "tanar'ri-ized angels," anyway, so making those protector spirits of old actual Angels and giving these guys the name is a good thing.
I'm also a huge fan of the reincarnation angle. I'm looking forward to these guys, and to the genasi. I think they'll both benefit a lot from 4e's "not just filling in the gaps" approach. "Aasimar" is a clunky name, whichever way you slice it.
However, I've gotta re-assert my disappointment in the tieflings. "Wangst" vs. "Poseur Badass" battles aside, the old tieflings had an interesting background in being the outcasts of a planar society that accepted everyone, calling in echoes of class divisions that really made Sigil sing with some Olde London kind of flavor. I wish they would've kept the "lower-class exile bastard-child orphan-on-the-streets" angle, instead of going with the old cheesecake cliche of a fallen empire of decadence.
Fortunately, the rest of the planetouched have always been a tad two-dimensional, so it'll be hard not to make 'em stronger with more attention given to them. Old school tieflings FTW, though.