It would be great if the visuals were modular, and downloadable to the empeg.

If there was a skeleton "SDK" for the modules, then people could write their own visuals at will. There would have to be information in the SDK regarding the available resources that a visuals module could call on (e.g. background real-time analyser process that shares info via shared memory or such like, how to draw primitives, etc.).

If a web site repository was established for the upload/download of visuals modules, then this would encourage the growth of free exchange of visuals, much like skins have taken off in a big way with WinAmp.

Finally, if emplode could create "visuals playlists" and could download a set of modules to empeg, you would be able to play around selecting only the visuals that interested you, and change them as often as you like.