All characters unlocked in ARAM
ARAM is a very casual gamemode, where I can learn matchups without the same amount of pressure on losing as SR. If all characters were unlocked for everybody to have randomely, there would be more variety to the gamemode, providing way higher odds of having a more dynamic matchup with more uncommon scenarios than before.
With the time it takes to even get hold of a character to learn them properly, it would be good to have aram as an additional source to learn about every character more in depth, not just from the weekly free to play rotations.
I would really like to see this tried out.

etc.