Tried double-tapping one of your movement keys?

Well, I love the game because AoE do matter and is not like in that other sparkly pvp where the zerg runs tight avoiding most of the damage and roflstomps the whole map.

On a more serious note, you must work around the AoE to make a success attack (and sometimes defense). Try to spread out, spam heals and cleanses, keep it moving and don't stack into a group or you guys will be roasted like delicious chicken nuggets.