This is a very good post.
Savage vs. Flair head-on is a tricky question, because you're effectively comparing the second-biggest legitimate star and powerhouse draw of the Rock and Wrestling Era for WWE behind only Hulk Hogan against the guy who spearheaded the NWA and was a consummate draw and performer throughout decades outside of WWE.
As such, I don't think there's any question whatsoever that at his peak, Savage almost obliterates Flair. Seriously. Savage was massive, a pop culture icon that surpasses Flair. Hell, "Macho Man" Randy Savage to this day remains something of a household name. Not to say Flair isn't nearly at that level. He's pretty close himself but Savage reached mainstream superstardom in a way that almost dwarfs Flair. Again, it's a tricky question. Flair had the greater overall career, the more legendary matches and experiences in multiple companies, territories, his career spanned such a long period of time and he's such a singular legend in the history of professional wrestling... Flair to me is the bigger legend, but all other things equal, Savage remains the bigger star. Again, the question is about who was the biggest star in their respective primes, and if we're going to be faithful to the question, I don't think there's any question that Savage was.
To put things into perspective, Savage was able to headline sold out house shows on his own over the Intercontinental Championship in 1990 and 1991. Even during days when in terms of the product he was utterly overshadowed by Hulk Hogan and The Ultimate Warrior, Savage remained a superlative draw and the second-biggest star of a generation in WWE.
Flair, meanwhile, remains the bigger legend. Particularly the bigger legend to wrestling fans. Every fan of wrestling that goes back any period of time is someone who knows Ric Flair. Deeply. And Flair was an international powerhouse. He could draw against any big name, anywhere.
So, ultimately, this is like comparing Jack Nicholson with Tom Cruise or something like that to me. Cruise/Savage penetrated mainstream popular culture to the maximum in the 1980s and remained enormous stars of their respective industries for a long, long period of time. But Nicholson/Flair date back quite a bit longer, were in smaller movies/territories, etceteras, have a deeper emotional connection, one could argue, with at least a couple of generations of cinema/wrestling fans, and are highly regarded as practically peerless among the stars of their eras-spanning stardom and success. Again, an extremely rough analogy. And I'm not talking about talent vs. talent here, just their career arcs and everything.
But really, at his peak, Savage was the truly bigger star, he had to be. Rock and Wrestling was a monstrous era for WWE and kids all across the country play-acted battles between Hogan and Savage for a few years in there the way teenagers in the Attitude Era spoke of Rock vs. Austin.
Of course, Flair as an attraction in WWE circa 1991-1992 actually surpasses Savage, because as WWE's front office recognized, Flair was already a legendary star from elsewhere, and would attract many wrestling fans outside the WWE wheelhouse. It's a key reason why Flair vs. Hogan was the ultimate dream match of that time period, the true legend still in his prime vs. legend still in his prime crème de la crème iconic match that went beyond everything else in the entire American professional wrestling industry. Unfortunately, through a bunch of mishaps and missed opportunities, it never came to be in WWE.