Why is everyone so against this?
TNA would be much wiser bringing in Hogan as a heel, as lets be fair, the majority of TNA fanbase is IWC, (or at least in possesion of more wrestling knowledge), and therefore the majority of the TNA fanbase is going to have some reluctance for Hogan coming in.
If TNA brought Hogan in, had him and Nash win the titles, grab the mike and have Hogan do what he does best, cut a promo, stating that he is blamed for taking down WCW, and that him being on top is detrimental to the product, before shouting something along the lines of "Well then this show is going down, because Hogan is bigger than TNA, Hogan is bigger than this stupid company, Hogans only here because his wife took some of his money".
Instantly, they have addressed the fear that he may book the company in a bizarre fashion that favours his friends, have the added bonus of keeping Hogan away from the ring by turning him into a booker, (A' la Sheriff Austin 2003). Then, on top of that, turn Nash into his snivelling sidekick. Have Lashley or someone bump into Nash in a corridor, and then film Nash running to Hogan and saying he has "no respect for us" etc, que Hogan starting to piss on Lashley, make Lashley win number one contender matches and have Hogan come out and restart the match, or make up some stupid rule that means the decision is reversed or void.
Turn Hogan into TNA's Vickie Guerrero, and then, start introducing Bischoff and Scott Hall, have a new look nWo start, only for AJ Styles (or another TNA's own) announce he saw WCW die, he won't see TNA die, and challenge New nWo to a match, have a young team totally outclass and run rings around the elders in the match, be realistic by having the old men not being physically able to match up, only for AJ to turn on TNA and cost them the match, make him the young buck who doesn't care about who raised him, he just cares about keeping his title, he wins a few matches through screwjobs, then have an even younger talent, (Eric Young? Desmond Wolfe?) beat him.
nWo kicks AJ out, and he is a similar character to the face Orton (almost).
Then have Dixie Carter do something, bring her on camera, say she has tried her best to make TNA grow, she has tried her best to make it a decent competitor for wrestling fans, and she was desperate so she brought in Hogan, announce that Hogan will be facing (the new champion) in a street fight, from which everyone else is banned from interfering, if (new champion) wins, Dixie takes away Hogans booking powers, if Hogan wins, then she signs over TNA.
Obviously, Hogan loses, and the programe ends, including the Nwo.
Hogan can go onto new programs saying he is better than any of these young bucks (que feud with AJ for the kicking out). And the title scene is freshened up by a new champion.
Of course thats just my oppinion on what should happen, whats more likely is Hogan will win the tag titles and become TNA's Triple H.