I suppose we just have different definitions on proactive and reactive. I Think of it in terms of ability useage, i.e. do you use it before or after you take damage. You think of it in terms of when the damage is mitigated, i.e. is it mitigated before or after it comes in.

This is why I think the intent is hard to divine. It's difficult to tell what the devs had in mind with this specific type of nuance, because so many of the WAR's available mitigation skills are meant to be used before the big damage comes in, even if the general idea around it is self healing.

I will just say in general that reactive abilities are also generally crappier because they aren't as reliable, and they are prone to having you die from burst, and they have a tendency to end up as overheal. Which is why moving Inner Beast to a pro-active shield would do wonders in terms of balance.