Oh, sorry, you meant input normalization, of course. Please please please also add output normalization, so all people in a room sound at the same volume!
I think it depends on which perspective your inputs/outputs are coming from ;) The way for all people in a room to sound at the same volume is to normalise the audio you capture from them. If you normalise the mixed signal you play back to the other users in the room, it's too late (at least if they speak over the top of each other), plus it'd be too hard as you'd be constantly yoyoing around.
