Serendipity
Explorer
I do think that the 4e aasimar/deva will be somewhat different from earlier editions (like the reincarnation stuff), but I can guess what the designers were thinking. Aasimar seems to be a somewhat unpopular and hard to pronounce name; since the aasimon/angels were reconceptualized, the word deva was just lying around waiting to also be repurposed.
*nodnod*
It just seems odd to me - I've never in decades of playing met anyone who mispronounced Aasimar....or Deva for that matter.

Digging what little I've heard about the new Aasimar flavor/fluff so far, much more than the Tiefling.