Earlier I start discussion:
http://forums.elderscrollsonline.com/discussion/111093/suggestion-rework-mark-target
It looks like it doesn't met with the approval
Ok, here is another one, but now my suggested fix is pretty simple.
Tags:
1) It is 4-th spell in tree, it should be stronger and usefull
2) 1.3.x is close, the developers have promised us some balance changings
3) The biggest problem what this damage mitigation almost useless. Why? Because reduction soft cap is 50%, so it doen's give any damage buffs (only debuffs for you), especially in pve. Hello light armor and alot of sets with such bonuses.
4) Nerf reaper's mark (no stacking buff)
Remake the core mechanic:
Player's attacks ignore x% of target's Armor and Spell Resistance, but target's attacks ignore x% of player's Armor and Spell Resistance.
and make it:
Player's attacks damage against target is increased by Y%, as well as target attacks by Y%.
over mitigation!
probably Y=10-20% will be enough