I'd probably have jumped on the AT-6 at age 25, and think it will be a very rewarding job for the RIGHT person. I flew the OV10 as a Lt, and it was a great seasoning job. We didn't have a real air combat mission as we were really just battallion ALOs on loan to the Army when they needed us, but it was cool mission anyway.
In Vietnam the FAC job could go to SAC, MAC, or TAC guys if they wanted it. Perhaps the T-6 could go the same way. While stick and rudder skills are important in COIN and FAC ops, they are probably secondary to good headwork and personal courage. I am confident we have aviators in a lot of different MWSs that would do a good job.
Single ship missions in an AOR, however, might be worth a hard look. Having an extra set of eyes to watch your belly and 6 could be huge in an area with manpads or AAA.
Haven't said it in friggin' years...but...."Hit my smoke!"