Okay, so (please allow me to try and make sure I get this) creating a custom extension which would allow viewers to send commands and receive updates in, maybe an external window of some description?
One thing I would like to do as well is keep any characters localized to the channel hosting the game, giving the streamer the option to load up a file containing info for all viewers who have participated in past and are currently in chat, or to start from scratch as they see fit.
(Just as a quick fill-in on the concept, it would be most likely an isometric overworld style map with little blips to represent the avatars for people in chat, which can create a ping for the streamer on the map when something particularly interesting is going on, for example, a group of chat viewers are taking on a boss or something. Keeping gameplay as simple as possible so that it doesn’t turn into too much of a mess. Or even having the streamer be able to join in on whatever the AI are doing, just to keep chat interaction high.)
I know this is kind of a lot to throw out at once, so thank you for your patience.