There are numerous things that I would do to "save" TNA. I dunno how much of it would work, but, I would do them never the less;
-Use TNA original stars at the top; For the diehards who have been watching TNA since the beginning, this has been an issue. TNA has been busy trying to sign big names and that's all good and well. Unfortunately, most of the former stars from elsewhere don't believe in being second to some "indy guy" or "unknown TNA star". This ideaology is WRONG! Any wrestling fan worth their own salt could tell ya that AJ Styles, Roode, Storm, Kazarian, Daniels, etc are all better than most of the "established" names that TNA have brought in thus far. I'm not saying don't use the other big names, just try leveling the playing field so to speak. Let the original guys win and main event with a healthy mix of the best of the established guys. Angle, Sting, Steiner, Jeff Hardy, Jeff Jarrett, etc can all be effective and still put over the core stars who singlehandedly built the current Impact Wrestling company.
-Change announcers: Taz can stay. He's funny and informative to a point without overdoing it. Mike Tenay HAS to go! Seriously, I hated him back in the WCW days and hate his style of matter of factly dismissing the other announcers and/or guest commentators. His voice is shrill and he needs to retire. I don't know who they could bring in, but, chances are they'd be better than Tenay.
-Build your divisions up. Make contenders. Define your divisions and build them up prestigiously so that each title means something.
-More emphasis on wrestling and less on entertainment; WWE has entertainment and they do it well. TNA needs an identity all their own. They need to go back to what made them in the beginning: kickass matches that defied expectation and innovated what is accepted as great. Once you do that, people will set up and take notice.
-Promotion. This is key. TNA has failed to create an identity of their own. Once they define their product, promote it. Don't do some crappy unreadable logo at the bottom of the Spike TV promoting Impact Wrestling on the night of the show. Promote it as if it's the biggest thing going on the network. If this means Spike can't do it, go elsewhere where that particular network will treat Impact Wrestling like the commodity it is.
That's about it. Once Impact Wrestling can manage these things, I think they will succeed moreso than they ever have.