I did quickly mention Sb Sheltron, however, surely the fact it went from damage mitigation + MP restore + Sheild Swipe proc to just damage mitigation shows that the intent is for it to be a mitigation skill only.

The problem with your Testudo idea, how do you track the cooldown? You can't track the cooldown of both Sheltron/Shield Swipe or Intervention/Shield Swipe on the same button. Could have a marker on the oath gauge to track it, but it would still need a way to show the cooldown ticking down. But that is a thought.

Also, I would not care if Vengence lost its counter hits at all.

Also, I would disagree with the philosophy that mitigating damage is made more fun when you add in DPS elements. This goes back to DPS > Defence. You are only using the mitigation to get to your DPS ability, it is just an extra step you have to take. You haven't made it more engaging, you have just made a part in your rotation to use it without thought to do more damage.