That's the thing. you are looking at single enemies when thinking about counters when you should be looking at the group. If there is a tank you know they'll taunt if other enemies lose enough health, but they can't taunt for themselves. So if there is a healer they heal the tank meaning they aren't attacking so their attacks take longer to buff. It also means no taunt so you can drain your target.
Tinkerers are the main problem because what they make decides if you run or fight. If the enemies double up then it depends.