I wish they would've tried to create Arena tournaments. I could well be proven wrong, but I believe Arena is a much less RNG-affected mode than people think. It's so much less optimised than constructed that there's a lot of space for elite Arena players to demonstrate their mastery and sneak out advantages. Games tend to be slower too, so there's more times you need to choose whether to tempo out or slow play, whether to use a removal or trade, or whether to flood.
Imagine a tournament format where each player drafts 5 decks for 5 different classes then selects 3 to play with, all in client, and without Mage being as insane as it is. Best 3/5, once a deck wins you can't play it again. Would be pretty tough for a random to luck his way to multiple wins against top 0.1% Arena monsters in such a mode, I'd imagine. 5 decks to choose from limits the effect of one or two rotten drafts, and not being able to use a deck that already won limits the effect of one insane deck.
When the drafting portion of the game is super-optimised, like it is in constructed, there's just not enough meaningful decision making going on in most matchups for the very best players to show how good they are. The recent Batstone tournament with bans was more interesting because the players had to find replacements for the obviously OP cards that were taken out.
