Good post. I differentiate here between the laining and Chazanus. As a part time lainer, I hate that singing along, it is distracting and you are trying to make no mistakes, or in some cases you have to remember certain trops,or pronounciations, if you don’t know them real well. I don’t like any talking at the Bima either,sometimes the Gabbai has to do something.
For Chazanus, to be honest, I will sing along, only in 1 Shule where I am related to the Rav and feel a comfort level, and its also a small minyan, AND, it’s a very long davening, and he speaks alot, so there is a level of boredom by Mussaf. Other places I would just go out for a break if bored, there I can’t do that so easily.