DPS players should focus fire to avoid getting aggro. If they are not, then that's on the bad dps players. Tanks should try to mark their targets so the dps know what to target. If dps players have difficulty with target selection, they should get used to macros. Even as a healer, I've been marking targets 1, 2, 3, and the tank will focus on 1 with the dps on it as well. I still get quite a bit of healing aggro on secondary targets, but I have a feeling that's been because the tank hasn't been using his abilities properly on multiple targets. I had one tank that basically said that he can only hold one target and that I must heal tank the others until he gets to them. Of course, I freaked out a little after dying a few times, but by the end of it, he was holding his targets like a champ. FF14 has an aggro system that requires teamwork and that's fine. Players just need to get used to this difference in gameplay from other MMOs.