Geneec
How an avatar looks as an imposter is often very different from how the regular avatar looks. A lot of avatars have per-user settings in the expressions radial menu which drive how the avatar looks.
* Height
* Color wheels for hue shifting of the clothes, body, fur colors, eyes
* Turning on and off accessories, clothing, or features
* Choosing between different meshes for parts, like horns, hair, and clothes
* Choosing different blend shapes which fine tune the avatar's look
Generally, imposters seem to generate based on how the basic avatar is modeled and how it's defaults are setup at build time, but people want to customize avatars, especially public ones and you can only do that from the client.
I propose a system where the user can queue the regeneration of their imposter from the avatar details menu, and have it submit a sort of dope sheet of all of the current avatar parameters. This way, when the imposter generator runs, it creates an accurate representation of the avatar as the person wants it to be presented.