Let me first say that player skill can almost always overcome class difficulties. That being said common sense must kick in somewhere. Rogues are capable of producing amazing damage, however they are simply not cut out to take on Raid bosses which can drop you in two swings. Clerics such as myself waste needless resources to keep Rogues up who decide to melee the Pit Fiend, due to the extremely short window of time to get that heal through.
Let the Barbs and fighters with 400+ hp stand toe to toe with the boss, while you range him from 30 feet away (still getting your sneak attack damange) while evading the blades and fireballs. Your Hp is a serious setback, just as a locked door is to a Barbartian