I have a Marauder and I understand to become a warrior at level 30 i need to have a level 15 gladiator. My question is this: Do i need to level the subclass on my Marauder or level a new character to level 15 as a gladiator or do both work? Also, for my marauder, do I need to start picking up gladiator skills soon to be an effective tank? I tanked since vanilla in WoW and do not feel effective gaining aggro with only one threat skill at 16.