This is exactly true. It's is difficult for the tank because there is no AoE Taunt at low level.
Playing Gladiator, as soon as I get to 1000 TP, I try to to use Circle Slash or Brandish, something AoE to get hate. But it's not enough. The heal is worth more, and a party heal, Sacrifice or AoE Cure, is even worse.
There are a couple tactics I've tried with parties:
1. Gladiator Provokes one and the Party can kill the other, with the other melee tanking. In this case the mages can cast heal safely on about the second battle round, after each melee has a minimum of two hits. If melee misses, they do not gain hate. Use Spirit Dart until Heal is safe, but don't be the first to attack the secondary mob.
2. The secondary tank engages first, and tries to get one to chase him. If the mobs link on aggro, the main Tank needs only to Provoke one. The rest of the party needs to wait until hates is established on both mobs to engage.
Mainly, I see Healers/Mages casting cure/spell after the melee takes the first hit, and they become a 2-hit snack. Mages have be low-key, wait for melee to engage, only cast their basic spell until they melee has established hate.
Any Gladiator Mains have some tips on gaining AoE hate at low levels?