I don't know exactly how credible Wrestlezone is, so people shouldn't be getting too excited about this. But if it is true (would like to see a credible source report it first) there are a few things to think about:
Hogan is bigger than any ten guys TNA has, his name is more recognizable to long time fans than TNA, he has stayed fairly relevant with his shows, people love the guy. But his name value alone wasn't enough to save WCW ten years ago and it won't be enough to even make TNA truly viable competition to WWE, he'd have to generate three times the audience TNA does and that just isn't realistic.
Eric Bischoff had a great idea and ignited the wrestling boom of the 90's, but his lousy leadership ability and arrogant attitude helped sink the ship faster than he got it floating, Hogan as well. Don't get me wrong, I think he's an entertaining onscreen performer, but his last great idea was 13 years ago and he burnt that shit to death, so what can he really do for TNA in a creative role? He won't have the resources he had in WCW and there isn't exactly hot names that he can take to stack the deck. Guys like Kennedy, Umaga, Kendrick et al, aren't exactly going to do for TNA what names like Luger, Nash, Hall, Savage etc. defecting to WCW did.
That being said, TNA, even if they went on a HUGE talent sweep, even with Hogan and Bischoff and eventually dead beat Flair, the ratings will increase, but not so substantially that it will re-ignite Monday Night Wars. Not trying to rain on people's parade, but that's how it is, it was big news 15 years ago when WCW signed Hogan, but for TNA to recreate that kind of buzz, they'd need to sign Steve Austin or the Rock, they are basically what Hogan was 15 years ago. Hogan to TNA is more akin to Terry Funk working for ECW, than Hogan to WCW.