Best advice i can give is to get a regular tank and get to know him/her. Time your AoEs to match his malice.
By the time you hit lvl 65 trials most mobs will be trash that really shouldnt kill you, but some can hurt like Hard so you gotta be wary of pulling them. On the bright side, these mobs temd to come in small groups or alone so tank should have an easier tie protecting you.
One thing I have seen a few magicians do is to let tank pull then cast resitance collapes and another buff/debuff to allow tank to build aggro, then spam AoEs.
At high levels you often have a second line of defence with you in dgns. Samurais make great AoE shields for you. They can take good dmg and have higher malice on mobs they hit than you do, especially with awakened katana and kp on ashura slash and purgatory. This means far fewer mobs will come near you.
Basically, at lower levels, AoE malice can be a pain, but at high levels, you'll kill mobs fast as Hard in a party, and in many cases, most of the mobs will aggro someone else rather than you.