So we get to dodge something we can't see from a mob that may or may not be visible because of server issues, that might not register what we're doing in time because of lag, and we get XP loss if we die?
I guess if you want to kill the game, sure. Fundamentally, you can't tune content to be a true challenge when you have an unknown number of people and unknown power levels, especially with an infrastructure that can't handle large scale battles. That's why instanced battles got popular in the first place.