Double Zero,
The OV-10's vulnerability depends upon what role it would fulifill. A manned sensor platform would happily work above the RPG/Small Arms threat, and a modern MWS/CMDS (coupled with a relatively low IR signature) mitigate somewhat the MANPAD threat. If the plan is to do low-level RW escort/FAC/CAS then, yes, the threat is higher. For intra theatre comms / light cargo role it would do the job between fixed sites quicker and cheaper than a RW platform.
The OV-10s biggest problem is that it's not a jet...and many people cannot get past that fact, much the same as the A10 has always suffered because it can't go supersonic...
As a low cost platform in a low tech war, a warmed-over OV-10 could make a lot of sense. The final decision will no doubt revolve around Congressional districts.