It reads like a pure support piece, and that is pretty much how it plays. The big thing is the uptime window is tiny, so it works best when you are already healing very often and not trying to force it as your main defensive tool.
For group content, the value is in smoothing damage for allies who are getting regular heals anyway. The armor proc is nice, but the real draw is the Minor Vitality, especially if your team is already stacking other sources of mitigation and recovery. It is less exciting for solo play, because you are spending a monster slot on something that does not really help kill faster.
HexRunner:
That matches what I was wondering. So it is more of a healer utility set than a tank set, right?