Just in case anyone was wondering–When you finish a match in Tombs of Terror your hero doesn’t show an experience bar, but you are, in fact, getting experience in the primary hero class for each hero. I assume they don’t show the experience bar just because the heroes are notionally duel-class.
While playing with Sir Finley, I hit L60 for Paladin (after finishing one match I got the “card unlocked” splash). I assume it’s the same for Reno/Mage though I can’t verify (I’m L60 with both Mage and Rogue), and I’d also assume it’s the same for Elise/Druid and Brann/Hunter when they unlock.