I think sometimes they do this just to watch us all gather the pitchforks.
From the updated PTR Patch 4.0.6 notes:
Fel Armor has been redesigned. It now surrounds the caster with fel energy, increasing spell power and causing the warlock to be healed for 3% of any single-target spell damage he or she deals.
Now THAT is a change I can get behind. Doesn’t have to be a passive regen, I’ll take 3% of my single-target damage. That should be plenty to cover my ‘tapping. Let’s just hope that this is the version that makes into live.