It's a nice idea, kind of like the way we get an xp bonus if we farm in a party, and like the set bonus from the new mythics.
It still wouldn't feel that fun for warriors though because although they would get invited for the set bonus, they would still feel a bit useless during the actual run if unable to group mobs, taunt mobs, or provide any significant advantage to their party other than this buff.
Class balance and warrior inclusion is about them actually being able to actively participate and contribute by playing their class skilfully- that's what makes something fun to play.
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