Well for one, Hall, Nash & Hogan arent some sort of unit with Sting so I fail to see the connection.
Hogan is under contract to WWE. Hall was not as big as Sting and is notoriously difficult to work with, has personal issues, has a pacemaker etc. Kevin Nash, I suppose you could. But he's in rough shape, even just to walk to the ring, let alone do anything physical.
Sting is a former multiple time world Champion and has a long connection to TNT and WCW. He cant wrestle but he isnt incapable of moving around, cutting a great promo etc.
AEW has shown they're pretty good as using the legends and I think Sting could serve a role there. Though I also assume Vince wouldnt allow it and would lock Sting up. EVen if its just Sting presenting the TNT Championship. If he wants one more match, he might be able to do it. I think he needs neck surgery though.