BlizzCast # 10 has been recorded and will undergo localization throughout the next days.  Zarhym confirms it will be available pretty soon.  You will get to learn more about the lore and design behind the Crusader’s Coliseum dungeon.

Blizzard Quote:
No one addressed the lore behind the tournament with the developers or why the Lich King is letting us run a combat fair in his back yard.

Zarhym: I’ll be discussing this in a little more detail in BlizzCast episode 10 with Lead Encounter Designer Scott Mercer and Senior Game Designer Dave Maldonado, both of whom have extensive knowledge of the Argent Tournament and Crusaders’ Coliseum in terms of lore and design. It’s already recorded and should be coming out pretty soon.