As someone who uses both PC and Mobile from time to time i have to say the viewing experince on mobile sucks. one of the many reasons is the video feed is landscape when most users are going to use their phone in portriat mode.
It would be great if streamers had the ability to send a dual feed, one in landscape for the people watching on pc, and one in portrait for the movile users .
I understand this involves a LOT of backend work, but with the large and growing precence of mobile users, being able to optimize the viewing experience for viewers on either will create a better experience. This will promote peopel to be around more often, leading to more viewers ect.