While someone has already suggested a channel admin role, it would be nice if the proposed admin has more powers than just adding and removing mods.
I am the head mod, editor, and essentially personal streaming assistant for a streamer that streams for fun and has a very busy and important life when not streaming. Even though he cares very much about his community and his stream, minor tweaks to things like info panels, adding VIPs, curating the autohost list, adding and removing extensions, telling me how many sub points he has, and editing channel points rewards often fall to the wayside in favor of his IRL job, personal life, and other business.
Various streaming tools and bots already have an administrator role that allows an individual near-complete control over the primary account-holder's account. It would be nice if Twitch created an admin role that had full access to the streamer's account, including editing info panels, so that we could essentially help manage their channel without having to be signed into their account and use their name, or have access to the stream key.
Obviously, this would be a precious role and streamers would need to be warned that this person has the power to change almost everything about their account, but if the streamer doesn't want to grant these powers, there's still the editor role that has limited extra abilities.