The warrior would either have to figure out how to cancel the epic's damage shield or switch to a very good 2 hander.

High DPS off of fast 1 handers really doesn't do very well against a mob with an 80 point DShield...

You swing at Jobabber for 68 points of damage!
You are burned
You have been hit for 80 points of non-melee damage!
You swing at Jobabber for 54 points of damage!
You are burned
You have been hit for 80 points of non-melee damage!
You swing at Jobabber for 13 points of damage!
You are burned
You have been hit for 80 points of non-melee damage!
You swing at Jobabber for 76 points of damage!
You are burned
You have been hit for 80 points of non-melee damage!

etc, etc. :)