The main change in the 13.0 patch is that doc team heals now cause aggro. This usually leads to dead docs. However, I find that this is mostly due to bad habits by the tanks.
I play a mid level enforcer, and I've found that I can control who the mobs target by using aggression enhancers (use a high ql one, I suggest something at least ql100). In extreme cases, Mongo Slam or other taunt nanos provide emergency backup.
Very often, when in a group with other tanks, I seldom see any indication of taunting (no blue aggro message floating up from the mob). Considering that the aggression enhancer has a recycle time of 3 seconds, it means that most tanks just don't taunt.
Instead the common tactic is to beat on the mob while the mob is beating on the doc. Hoping that the damage dealt will pull it off the doc. That tactic unfortunately no longer works.
So all I can suggest is if you play a doc and get into a team in which the tanks don't taunt, that you quickly leave before you get killed by an aggroing mob.