Wrong. Hogan wasn't even the first choice to head the nWo, it was Luger. Ask Monty. Yeah a stable of Hall, Nash, Perfect, Bret, etc... would have just tanked. 
And thinking Hogan sustained a bigger reaction from the fans than when the Rock returned is laughable. I'm not a Rock guy, but he was at least as big a deal returning and sustained a longer pop than Hogan.
I know Hogan wasn't the first choice. It was supposed to be STING, not Luger. A major over babyface had to be the 3rd guy. But, Hogan was the better choice than Sting, anyway. Two ex-WWF superstars joined by the BIGGEST WWF superstar of them all.
As for Hogan and Rock, can you say WRESTLEMANIA 18? Even before then, when Hogan accepted Rock's challenge and later got jacked by Hall and Nash, Hogan was actually getting CHEERED (as a heel) for whipping Rock with his weightlifting belt. At 'Mania itself, the fans were BOOING Rock and cheering Hogan. Chants of "Rocky Sucks", which fans hadn't been using in years, were echoing throughout the SkyDome.
Hogan is like Arnold......Flair is like DeNiro. You prefer comic books and I prefer War and Peace..... Hogan is the biggest draw ever, but Flair is the greatest wrester ever.
It's like saying that some American Idol winner is a better musician because they sold more albums than someone less known, but who put out far superior music.
One closing thought, Flair could put over a broomstick in a match, Hogan could take another star and turn them into a broomstick.
Anyone in a match with Hogan was in the "Main Event". Hogan's career has been almost as long as that of Flair. So, your comparison is rather inaccurate. Their careers have paralleled each other. And Hogan has had the better deal. He became the face of WRESTLING, not just a particular company, but the business itself. Again, Hogan not only ruled the WWF, he also went to Flair's turf and outshined the Nature Boy there, especially when the NWO was formed.
If you'd said that anyone would be a bigger heel in WCW than Flair, people would have thought you were nuts. But, Hogan did it and it shocked the wrestling world. Luger turning heel? BIG DEAL!! Sting.....Possibly!! Bret Hart? BIG WHOOP!! But Hogan...........that was HUGE.