...I wish for 5.1 (6 channel) implementation.

Not in the traditional sense, but 5.1 sound would be fully supported. That isn't the point though.

But this could allow source-splitting for people who want to broadcast a whole bunch of stuff but separately, like streamer's microphone on track one, videogame on track two, music on track three, sfx/dono sounds on track four, victory music snippets (think 'we are the champions, but a 5sec version) on track five, etc etc.

This could work for talk shows, musicians, concerts and so on and so on.

This could come as a beta feature with each track at like 64kbps, or even higher, and would then offer the viewer the choice to turn up/down independent channels or even mute the ones they don't want to hear. This could even allow viewer-side fine tuning if there's a debate or something and multi-source is set up correctly where viewers can, as previously mentioned, turn sources up or down.