Arena is about drafting troops like a player would draft cards in Magic The Gathering or Hearthstone, but regarding such systems MTG always had the benefit of allowing you to select MORE cards than you MUST use.
To give a short summary: You will pick a total of 42 Non-Basic Land cards and you must create a deck with AT LEAST 40 cards counting Basic Lands you can add (which usually means a split of 27 Non-Basic lands and 13/14 Basic Lands for a functional deck.)
GoW fails with Arena because we are not offered enough options, if you are offered poor options all around¹ then your team will be very weak, more so without the Hero.
Now if the devs would have engineered the New Arena in a way that after each battle you could pick another troop (maybe of higher rarities included) from among three other options then we would have an interesting experience. Because if your first four options were bad and you had a loss you would still have another chance at picking another troop that could help you build a better team.
This could also be expanded in a way were you could be able to unlock the traits of one of your troops as well as selecting one new card to your temporary collection.
¹ And considering some troops are stright up bad even for Arena because the devs didn’t focus on making more rebalances when the world wasn’t cursed we can only accept that now it’s even more unlikely that anything will be done in that regard.