On the other hand... - Edit 1
Before modification by Etzel at 06/10/2009 09:40:03 PM
Though it seems unlikely that he would be given another body, given how easily he was killed both times.
I'm not sure the ease with which he was killed both times is a factor. However, at this point I don't see any strategic reason for the DO to resurrect him again, unless some of his scientist skills are needed. It's probably too late in the game to place him as an undercover agent somewhere, as he was as Dashiva. And the DO doesn't really need him as a weapon during TG, now that he has a bunch of Dark Asha'man at his disposal. And Aginor was never a key general or combatant during the AoL, from what we know, so his usefullness as such is questionable, anyway.
So I don't see him returning either, even though I think the DO was able to capture his soul. We have no reason to believe otherwise - Ishamael was killed with callandor, and the DO was able to capture his soul. So he ought to have been able to capture Osan'gar's soul too.
Why not transmigrate Osan'gar, if the DO can easily do it without any cost, and e.g. give him then to Moridin as an additional, maybe mindtrapped servant? Osan'gar is after all still very powerful and experienced. We also know from RJ that the DO prefers his original Forsaken. Plus, Osan'gar didn't betray the DO. Just the fact that he was killed by enemies (or actually Elza), shouldn't stop the DO to transmigrate him, if the promise that Forsaken are basically immortal has any validity. Also the extra chairs at the Forsaken Garden Party in KoD could point to a transmigration of Osan'gar.
I think a transmigration of Osan'gar would definitely make sense for the Shadow. If RJ didn't do it, the reason is probably just plot-related, namely that it would be a bit lame to have one Forsaken transmigrated a second time in yet another body (though one could also say it would be a nice twist, because few would suspect it).