The only TNA talent I could see WWE interested in immediately is Sting, Kurt Angle and Jeff Hardy. Maybe Bully Ray to help bolster the heel roster.
Other than that, the guys that have stuck it out with TNA are too damaged.
Ring of Honor would benefit greatly, though, if WWE bought and closed TNA.
But don't kid yourselves... WWE won't spend a huge amount of money on TNA. They could probably care less. If Bischoff, Jarrett or Viacom pony up more money, Vince could care less. It's not like TNA has a great video library like the WCW or ECW had.
What about AJ Styles? Or do they already have their quota of "AJ's" on the roster?