Suggestions for better gameplay in Competitive Brawl. This is based on game experience and years of playing Duel Commander. I believe that at some point, Competitive Brawl can translate to paper, and I want to be part of that drive.

Suggested Format Changes –
Aside from game data, player feedback and gameplay should provide insights on what cards are unhealthy, and more importantly, what’s not fun for gameplay. Aside from my experience with years of Duel Commander tournaments, the below changes and banlist suggestions is based on my current gameplay in competitive brawl. I believe there’s tons of potential here, where the format can be translated to paper at some point.

A meta where Burn can’t check strong decks, is unhealthy. Lower down starting life to 23 or 20. This allows FAIR aggro decks to match up against heavy control and quick combo decks.
Banlist Suggestions
Ban as commander
Derevi
Ban justification
Although rare in my game logs, I don't remember ever winning against a Derevi deck, regardless of which commander I used. There's a reason for it being banned in Duel Commander, and which should justify the banning in competitive, or even just Brawl in general.
Bypassing commander tax - The ability to flash in a commander without restrictions and gain command zone advantage. Unless you tax the ability, then this is ban-worthy
Enables tempo abuse with tap/untap ability, and synergizes perfectly with Winter Moon.

Yuriko - Oversaturated in the meta.
– There’s a reason why she is banned in duel.
Bypassing commander tax - Entering play for 2 mana, gaining unavoidable damage, and card draw for free, compounding the ability when you have extra ninja's provide OP advantage. If you aren’t the starting player and is unable to mulligan for 2 straight removals, you will almost always lose.
The meta data should already explain it.

Nashi - Another brawl meta staple.
Sultai colors provide maximum value for blinking and tutors that are given free when Nashi resolves. All the more, it provides flexibility on providing the player on what you need in various situations technically for free. Need a creature, need removal, counter, combo piece (Oracle,Tainted Pact). What do you need? YES.

Emry,
Ban Justification
Requires high artifact and graveyard interaction. Cheats Commander Tax. Easy to pull combo wins.

Uro –
Ban Justification
Consistent card, land, and life advantage, given that graveyard is far and few, plus, it's easy to fill your graveyard, making it almost unbeatable during mid and late game. Same reasoning where Burn us unplayable in the format.
Urza, High Lord or Paradox Engine - Can ban either or.

BAN in 99
Natural Order -
Provides a cheap (4cmc for green can be done in turn 2-3) tutor-to-play advantage. Llanowar Elves to Eldrazzi. Nuff said. Llanowar Elves to Atraxa

Channel - Turn 2 Eldrazi, Ugin, or any other colorless spells. Mike and Raph on turn 3 too, paired with other fast mana.
Chrome Mox. Llanowar Elves, Exploration, Utopia Sprawl, Burgeoning. Dead if you don't have interactions
Wary Zone Guard
- Highly oppressive creature. Land recursion, 3mana 4/4.
Watch list -
Lumra - Recently banned in Dual Commander due to it's resilience in during mid and late game, making it difficult to win against.

Ban Stripmine, print Wasteland, especially with the rampant land GY recursion from green decks

Library of Alexandria - Provides unparallel card advantage, esp for control decks., allowing them consistent card draw without penalties.

Arena nerfs –
Un-nerf
Not all Arena nerfs are bad, but some can be reverted back to their original ability.
DRC - 1 cmc 3/3 flyer once delirium is met can still easily be interacted with. It's the Surveil ability that provides more value. There are a lot more toxic cards than this one being nerfed

Orcish Bowmasters - The inherent ability keeps a lot of abusive draw abilities in control. Creature can also be easily be removed. This is not an oppressive card in competitive brawl.

Winota - A bit hit and miss. 4cmc creature can be challenging to cast without a lot of ramp such as 0cmc artifacts (lotus petal, mox diamonds, etc).

Galvanic Discharge - Given that the format has a lot of creatures have more than 3 toughness, Red needs more consistent 3 damage removals, energy itself is not a factor as it can't be abused in 1v1.

Nerf
Seek abilities – Now these are oppressive in the sense that it can’t be interacted with. Free resource with no penalty. Not all colors have stifle effects to prevent a seek ability, and can't be countered with can't search abilities.