Imo, given gamers and their fascination with pushing boundaries of rules, decorum, and common sense, such a creation would lead to meta-pvp where people would get set up to die, i.e. "accidentally" pulling too many mobs, dissolving teams when teammates are sidekicked and in an area their true level should have no business being in, and god forbid you enter an actual pvp zone.
Presumably making 50 mean something again precludes exp boosters and not grouping for fast easy exp to get there, and with everyone slowly, inexorably giving in the paranoia of everything in the game trying to end their career, no more teams form, the alphas at the top start feeding on each other, and there's nothing left to do but dfb and street sweeping in Atlas Park.
Congratulations, youve made love not warcraft.