Not sure about character links on the X. What does the table do for that if you have multiple wins with that combination?
Though if we can ask for the whole arm, lets make sure to get a way to denote 30/60 wave wins for the arena (separately), and a tracker for the highest depth to the infinite dungeon reached with that class combo. replace the X's with simple graphics and do it all on current chart, something for game win, silver trophy for 30 wave win, gold trophy for 60 wave win (use the current cheevo graphics if nothing else), and a number for the ID. (Add E, A, and R letters to each graphic for difficulty) Would be a simple enough change, and prevents needing to add a new chart.)
Edit: Don't forget that we still need a cheevo for a win with every race, every class, and every (valid) combination

(Still like 'Like a Dimwit' for the last one, in homage to such a great player.)
Edit Again: For that matter, how about a class mastery achievement, or a race mastery achievement? In addition for cheevos for winning with every race, or every class, how about specific things like "Anorithil Mastery" and "Shalore Mastery" (Or other classes, or other races.) for clearing the game with EACH possible race of the Anorithil class, or with EACH possible class for a shalore. Again, it's about giving incentives to make people WANT to fulfill all of these things. (And gives smaller goals to aim for along the way.)