It probably depends on how long he stays a catcher
He already has the most batting titles as a player at the catcher position and a good defensive catcher at that. One more batting title as a catcher would serve him well.
His fellow Cretin-Derham Hall Alum went to the Hall of Fame playing half of his career at DH and was an average 2B/3B the other half. I am not too sure many would argue against Paul Molitor's inclusion in the HOF.
Not to give Mauer too much credit, but he is 29 and has a ways to go in his career. A career of which, I think will make Twins' fans proud.