I don't really see a huge problem with either one, honestly. I will say that Joe Mauer's peak was "best player in baseball." Molina has had lots of longevity as one of the best catchers in his generation, and that's very rare too. Mauer has a decisive edge in WAR, or JAWS, or peak, or whatever you prefer there. Molina has a decisive edge in durability and, well, actually being a catcher for most of his career. I do think Joe Mauer is a hall of famer, though I'd be shocked if he's in on the first few ballots. Concussions cut short the all-timer trajectory he was on. Molina I'm less sure about, but it wouldn't bother me much if he were, especially if you believe that catcher defense is undervalued in the stats (and I do). As a pure catcher, it doesn't get much better. Not these days.