a VERY simple idea...
Just in Cyrodiil and battlegrounds... cap any damage up to 10k to light armor, 8-9k to medium and 7-8 to heavy (except executes) and cap Burst heals also?
more counterplay, skilll, etc, without ruining PvE, but also preventing any kind of one-shots (looking at you buffed 2H ult.)
It wouldnt also really destroy builds or gameplay dynamics... dunno, just throwing it out there...