Collecting all the TT cards forces you to engage in almost every facet of the game. This is just another one of those. The players that have all of the cards have touched almost every aspect of the game. I fully expect that Beastmaster will have a card locked behind it too.

If there's one thing I wished they would change are the TT drops from 24-man dungeons. They should make those like untradeable minions where you can't lot on it if you already have it. But change it to Greed-only for those that already have it. And Need otherwise. It apparently is too much to ask the playerbase to respect Need before Greed. But that's how it is.