Reactive Regen in its current state is over performing to a monumental degree in certain PvP rulesets, to the point that PvP Brutes/potentially Tankers can effectively be made entirely unkillable in a 1v1 scenario while running Reactive Regen (on top of other effective mitigation tools, naturally).
After a lot of testing with this, it's brought Regen in PvP from the unambiguous top of the heap back to a comfortable position as a very strong set. I was startled by the .8 and .08 scalars, but neither of them through a series of different tested builds felt like they were necessarily cutting down on the effectiveness of RR in any serious shape. It just meant that there were actually opportunities for someone to be able to beat a Regen Brute again.
It's a good fix. I maintain that putting it at a 1.0 scalar would make people feel less scared, but the .8 is really not as drastic a difference as it seems.