I've been waiting awhile to get into this thread! I know it's dead atm, but just to chime in some.
I think the analogy to GWE has to be adjusted somewhat especially on Great Match Theory vs. Great Movie Theory. First of all, if you want to go by great match theory, it's an easier fit for movie directors than actors because directors have more control over the quality of a film, almost always, just like how a wrestler has more control over how good his promos are or match quality. Actors, for the most part, don't have that kind of authorship over their movies, unless they are huge movie stars, and usually that's still only for certain projects and while they are on top. For that reason, I'd go more by looking at performances within the movies rather than simply if the movie is good or bad because so much can depend on the script, bad editing, poor directing, etc.. Sometimes an actor can be awesome in a shitty movie (for instance, Philip Seymour Hoffman in Along Came Polly), and sometimes a movie can be quite good despite an average or weak performance.
Not bad :-) ... O'Toole did have some major stinkers on his resume (Caligula, Supergirl a.o.), but I guess you'd call that "old man Flair" and then the last few years where O'Toole did stuff like Venus would be Flair's retirement match and some other ok stuff... I could see that.
What about Flair = Jack Nicholson?
Caligula isn't a good movie, but that's not on O'Toole, I think, even if he is giving another variation of the yelling King performances he had given before.
Jack Nicholson I can definitely see. He got into the movies early, but he was at an older age when he started to become a star and has a lot of varied performances throughout the 70s. Then basically he becomes more and more Jack being Jack the movie star, which is awesome, but somewhat descended into self-parody at times. However, for the most part, if we look at movies as the measuring stick he stayed pretty consistent whereas Flair dropped off more. But you could argue Jack wasn't as great in some of those later roles, even the ones that worked--I liked him in the Departed, but I know some people aren't crazy about that performance even if they love the movie.
Their performance styles are very different but when I think of Flair and comparing him to an actor: I think of Flair as Robert De Niro. An extremely ridiculous and nice run of performances from the early/mid 70s then he starts to downshift slightly, even though he's still in many good movies for awhile, and then after about 1998 (Ronin/Jackie Brown--I love that movie!) he descends into comedy--which can be entertaining--or just phoning in it and declining. It's really striking how quickly he descened into Showtime and Rocky and Bullwinkle territory and then barely ever dug himself out. But, here and there in the last few years, he's churned out some solid, if not spectacular performances--for instance, Silver Linings Playbook and the Intern (bad movie, but solid De Niro.) Not great, but some nice flashes. Still...you look at his resume, and there's no disputing he has to be up there in the GOAT film actor discussion, and probably the guy most actors today would pick.
Duvall is a good call for Arn. I'd argue Philip Seymour Hoffman fits too, although he's become more acclaimed and recognized due to his death. Both were usually put into smaller supporting roles, and both were extremely consistent.
Depending what you think of Eastwood, I'd argue you could compare him to Stan Hansen. He's definitely got a particular style and doesn't range too much out of it, except occasionally, but he's so good at it and iconic that he can succeed with 2 pitches to force a baseball analogy. Along similar lines, Samuel L. Jackson.