When in missions, I find it annoying when i want to say something in the mission and it gets sent to squad members aswell. When i'm in a mission and want to say a guild message it gets sent out as mission message as well.
My idea is for there to be some sort of way to choose which type of message you want to send. Maybe there could be another chat button for when in missions and that gives you the option for messages and sounds. It's just an idea but i think it would help a lot.