Come on now, this isn't even an issue. In 24-mans there are at least 3 tanks. So if the MT dies to the raid boss, you have 2 other OT's available. Provoke the boss, and start building your enmity combo. You shouldn't be advocating a method so fragile as provoking off of the MT while he is still alive just for the purpose of becoming 2nd on the enmity list, while also risk turning the boss around. Please don't do this. That's just bad tanking conduct.
tl:dr: Save Provoke for cases where MT dies/tank swaps. Not before.
