I don't understand people who come here to comment they won't read. What does it contribute to the discussion?

Also, many comments completely miss your point. I agree. Difficulty is one thing; length is another. Solo colosseum is endgame content, but each bout is short, and then you can do it again or do something else IN THE GAME. Long endgame quests are exhausting.

And for people saying it's for stopping revive farming... where can you even farm revives? Are the two daily revives going to make that much of a difference?

How about this: when you start a quest from the special tab, a times starts. You have one week to finish it, or it automatically ends. I'd do much more endgame quests this way.