This is not going to be answered here you need to talk to the engineer who designs the trusses and you will need a new permit so it is worth it to have higher ceiling in a sapce you sleep in for me not Then i do not like cathederal ceilings anyhwere they distort sound add huge $$$ to heating and cooling and IMO for no purpose .

Building Dept very well may require it as the roof was presented and engineered with a completely different support system. I would not worry that other people here like or do not like cathedral ceiling, it is actually not part of the question, however I would want to make sure it was built properly and a potential hazard.

Come up with a roof design that will properly shed water from the roof first. Keep the architect in the loop. They help protect you from you.