Would there be a way to give the players the ability to toggle the death notes on and off?

Not at the moment, however I'm hoping to update Death Notes soon to allow for another plugin to add that functionality. It's not going to be a part of Death Notes itself since from what I've seen the majority of Death Notes users didn't need that feature in the past.

Yeah I am just noticing some people requesting it the higher the server pop goes, as it does spam the screen quite a bit

Second this. When the server gets 100+ people on it the deathnotes can get out of hand. An option for players to turn them off would be amazing.