I have a few suggestions for the custom game settings and would love to share them here so that maybe we could get more wild with our custom games.
Last night my friends and I used the somewhat limited stat adjustments (increase hp, damage, move speed, etc) to set up what we called boss fights. We gave the boss player 200% HP, 40 CDR, and 10% move speed, and the team of 4 were given normal stats and -60% damage. There was one small problem... Whenever someone wanted to the be the new boss, I had to manually change each player's stats. This is where my custom game settings ideas start to come in.
Team specific adjustments
Having team specific stat adjustments would make doing the whole 'boss fight' setting much easier to set up and enjoy. Being able to make pink team have 50% increased health and -10% damage while the red team has max cooldown reduction but -90% health would be so much easier than having to switch to 'per player' stat adjustments.
Character specific adjustments
To follow up the team adjustment idea, it would be nice to further adjust characters per team, only taking priority if they are not default stats. I know that you can remove character specific cards from the pool, but not being able to adjust their stats individually is kind of a bummer.
Automatic randomly selected cards.
When we did 10 cards as a joke, it actually became a total slog and my friend asked if there was a "auto random," to which I found out it was not a setting. This, while seemingly simple, would be a huge QoL.
These 3 ideas would carry custom settings a loooong ways. We can already save 5 presets which is wonderful, but it's not really too useful unless you have really picky friends or you can come up with game modes already with the limited selection currently available.
Here's a little clip from our boss fights we did. I hope some of you like this idea for expanded customization.