Brawl....
To my fault, I only really enjoy playing arena to play brawl. As such i build casual decks just to grind out the daily challenges, such as attack with x amount of creatures. I am finding it very hard to play arena at all lately, as I feel like I am constantly paired against competitive decks, or completely decks that counter what I am trying to do. Usually before the game fully starts. Constantly whenever my daily challenge is attack with x creatures, for example, I end up queueing into decks that are just pure removal, or a combo deck winning on turn 3 or 4, before I can even attack with more than 1 or 2 creatures.
My suggestion is a better system for brawl pairing or alternative mode for it, where the power levels are more adjusted. Such as implementing a mode with restrictions, or one where you have a weighted deck construction, being able to see the "value" of your deck during construction and there being different "rank" queues associated with the deck values, so you can see what youll q into.
Also, Mana drain is INSANELY terrible to play into. In 4 man free for all, sure its balanced by other opponents. In 1v1 its terrible, and scales immensely based on the strength of the deck playing it. Even when mana drain is countering a turn 2 mana source, the opponent having access to 5 mana-minimum turn 3 while being up on tempo is usually game-defining. 95% of the games ive tried to play through a mana drain just end in a loss 2 or 3 turns later.

At the moment, it always feels like, unless playing high power brawl, its going to be a terrible time, and incredibly difficult to even achieve completing daily challenges. Many times the game is decided by turn 3 or 4, and games end up a landslide in one favor, and not very fun to play. Brewing fun and interesting decks becomes stifled by the need to play strong cards to function, the same cards in almost every deck, homogenizing the colors, and making many decks just feel the same.

Side note- very interesting that I only ever see Ragavan brawl decks, when playing Ragavan. Not complaining, honestly find it funny.

It could be a very fun concept to see a queue for Brawl and another format that is heavily restricted and meant for doing daily challenges. Similar to starter deck modes, having pre-constructed decks meant for achieving specific daily achievements and either being assigned a random deck based on the players currently active challenges, or being able to choose the challenge and getting a random deck from a pool for that challenge so its not the same deck everytime and monotonous.