The direction the battles are heading in FFXIV with individual combos from everyone, including the tank, and battle regiments later on will allow for more engaging and dynamic battles (Hopefully).

What you are suggesting is simply making one of the damage mitigation skills to be renamed as blocking/parrying and have a set amount of damage that it can absorb, like Stoneskin or Phalanx. For the moment, without really looking at how battles will be come 1.20, I would say wait until you try how battles will play out.