how reasonable is it to do Brawl draft? deck size is 39 cards (including basic lands) plus the legendary creature as commander. Otherwise it’s identical to a normal draft.
there are a few problems I have partial solutions to:
Problem 1: color identity and minimum deck size meaning you don’t always have enough cards in your commander’s color identity to build a 40 card deck
Solution: Any cards you drafted can be included in your deck, just like a normal draft. However, you can only include basic lands that match your commander’s color identity. So you could totally splash off color, but it may be much more difficult/impossible to cast those off color cards.
Problem 2: never drafted a legendary creature
Solution: Solution one is to have a number of legends set aside equal to twice the number of players. Before drafting you would give each player two of these at random. They would pick one and pass the other to the player next to them (left or right determined randomly). Players could use one of these as their commander OR any other legendary creature they happen to draft.
Solution two for this problem is a player can designate any other creature as their commander. They have to tell their opponents beforehand and show them the card that represents their commander.
Solution three is they get a placeholder vanilla commander with stats as follows:
M 1/1
MN 2/2
MNO 3/3
MNOP 4/4
MNOPQ 5/5
where those letters represent increasing numbers of colors. So M is a mono color commander that costs one of that color mana and is a 1/1. MN is a guild commander that costs one of each color and is a 2/2. So you’d always be better off drafting an actual commander but wouldn’t be DQ’d for not having a commander from the draft.