They’ve really designed themselves into a corner with this one.
Healers are powerful enough and resources are plentiful that simply dealing more damage as a failure mode doesn’t work in the current meta.
Either you throw out damage downs to the point where it stops you beating enrage or you one shot people.
The only alternative I can see that actually punishes sufficiently would be bringing back the old petrify punishment. That was a good one and I’m sad to not see it in a while. It generally meant you were going to die to a following mechanic but it also gave healers room to try and pocket you through it which was surprisingly good fun