I would really love if we could set a specific avatar's impostor as our main fallback that appears regardless of what avatar is currently active.
In a lot of cases, using an impostor is way more convenient and sometimes even produces a better-looking result than making a custom global fallback, so I'd like to just choose one avatar's impostor to be displayed when impostors aren't available for other avatars I'm using.
I understand how this suggestion could become pointless when impostors are eventually generated automatically for all avatars, but I thought I'd ask for it anyway as there still could be use-cases for it in that context. Like desktop-only non-humanoid avatars that can't be impostorized, for example.