I dislike the brawl format for draft. I find it tedious. Rather you fight one match at a time (like ranked) from a pool of people with similar records.

On topic of people keeping contents from packs, that will devalue packs significantly. (Infinite print basically.) So I think it would be better if people don't keep the cards outside of draft. (Hearthstone Arena does this.) Plus, cheaper entries as a result so you can play it more.