If they signed him that would do for Anderson in TNA... Whether Vince would have him back is debateable but I could see Anderson saying "not worth staying if this is the level of talent you're bringing in".
Not sold on Holly as a trainer, as once you've broken trust with a rookie worker it's hard to get that trust from other rookies in the same way Hogan's "Hiro Matsuda broke my leg on day 1" or Dungeon stories might have deterred some legit talent back in the day from going to those schools.
Guys in OVW might be wary of Holly or seek to "push his buttons" to build their own reps... Bill DeMott learned that that being "tough" does not always translate to being right, sure the complaints against him about the "naked wrestling" and pushing talent into injuries fizzled out but the damage to his rep, whether justified or not will remain. The one way I see Holly working as a trainer is under Al Snow, the two have a good relationship and Al being the senior guy might keep Holly's mean streak in check but ultimately what would he be teaching them? He was lower mid-card for 10 of his 15 years in the WWF and only really got one proper run. He's not exactly teaching for success. To be fair that can be said of a lot of trainers but at least WWE has agents and producers who HAVE been main eventers to mentor the talent once they're out of the basic training stage... TNA doesn't have that.