New arena modes are cool and everything but is this REALLY what was needed to make this gamemode playable again?
Some of your classes are undoubtedly OP like priest generating endless value such as big removals and healing. You can’t neither outvalue them nor kill because they have TOO MANY lifesteal creatures and spells generated by their imbued hero power - this is ridiculous. The most infamous one is 1/3 taunt which gains 3/3 if you’ve used your hero power this turn (of course you did, this very card is generated by your hero power!).
I’m not raging at all but priest and maybe shaman classes feel like too much simply because of their imbued abilities which makes Arena neither balanced nor fun if you’re not given an option to pick such class. And this is only one problem out of two!
Kinda strange to make an Arena rework without huge rebalance since in every Arena discussion 90% of opinions are “Arena in its current state is just taking 3 wins - 3 losses until you randomly get OP cards and craft an OP deck”, and as an old Arena player with pretty good winrate in the old days I totally agree. Every single game is just a race of randomly generating legendary, randomly generating mass-removal. So my opinion is that Arena’s pool should be restricted once again like when you removed notorious Flamestrike from common Mage pool 
But now the problem is much bigger.
Arena hasn’t been fun for a long time, and while Constructed has survived its worst days and is fairly fun to play again, Arena has become something as awful and uninteresting as Constructed was during its worst meta. So for now, the most interesting format for every Collectible card game, so-called “Draft”, in Hearthstone is kinda… Dead?