As someone who has done some casting and follows a number of tournaments in the client, the open mic is a blessing and a bane. The number of times you come across casters who've forgotten to do this simple thing (turn on the open mic) is frustrating to say the least, and as a caster I know that I've not noticed I've forgotten this until sometimes up to 10min in.

So I think it would be nice if, when you enter the Broadcasting slot of a lobby, your open mic gets turned on automatically and your co-caster gets automatically muted.