I was just testing out a Dervish build using 12 Mysticism + Pious Renewal to have enough energy to fuel Vital Blessing + Protective Spirit + Spirit Bond while wearing no armor except shoes (for a rune and +1 energy pip). Any hits that would normally strike for 20+ damage now get bumped up over 60 (if they hit anywhere but your feet), then capped to just over 60 by Protective Spirit (because Vital Blessing boosts your max HP just above 600), thereby setting off Spirit Bond to heal you for 70-80, and you actually have enough energy to keep them all up (and lose little energy even if they're stripped). I solo'ed the Zaishen Obsidian Spike group (yes, 1v4) without trouble. Throw in Reversal of Fortune for some extra healing and it actually increases your available energy (costs 5 to cast, you get 6-8 when it ends).
Unfortunately, there seems to be a few too many sources of low-damage hits in real PvP to make it effective (someone torched me with one of the Conjure Element enchants as soon as I tried it in RA--you take around triple damage from anything that normally hits for under 20). It's highly vulnerable to, for example, concentrated wand attacks, since they usually hit for under 20.

It's too bad--it would have been really fun to watch the consternation as the enemy team focuses powerful attacks on the naked Dervish and can't seem to bring her health down.
It ought to survive against the Sand Shards exploit build that's running around, though, which I find highly amusing.