Eh, just because you have personality and can cut promos pretty well doesn't necessarily mean that you'd be a good commentator. Frankly, Hulk Hogan is a huckster. I don't mean that as a reference to the WWF commercials back in the 90s featuring parodies of Hogan, Savage and Turner; I mean that Hogan is a shameless self-promoter who is far more interested in being in the spotlight than anything else. As a commentator, Hogan wouldn't be in the spotlight and he'd have to spend his time, whether he's a face or heel commentator, putting over the talents of other wrestlers. I just don't see Hogan being able to do that for any reasonable period of time.
When it comes to Hogan returning to WWE, I've got no real interest in seeing it happen. Hogan's been in TNA for nearly 3.75 years and, during that time, the value of the Hulk Hogan brand is vastly less than it once was. For the better part of 4 years, Hogan has been one of the central figures in TNA. Quite often, Hogan has been THE primary focus as a babyface or heel despite the fact that he hasn't been a relevant draw for TNA any more than any other member of the roster and that he can't really wrestle anymore. IF the various reports are also true, Hogan's made a lot of money from his deal with TNA as, allegedly, Hogan gets paid $30,000 per appearance.
In the grand scheme of things, I don't really see what Hogan has to offer that would be of any real benefit to WWE. Oh, I'd say that Raw could probably pop a rating for a week or two due to people tuning in for the nostalgia of seeing Hulk Hogan back in a WWE ring. Because of Hogan's past glories, him coming to TNA felt like a major deal and a signal to some that TNA had arrived. WWE doesn't need Hogan to be a major deal and hasn't for a very long time.