There is no other way to really say this other than the fact that Replenishment is pretty overpowered in arena right now and will only continue to get worse as gear improves WOW POWER LEVELING. This is the single biggest reason (at least in my opinion) why ret/healer 2v2 teams and holyplay-type comps (double healer/ret paladin 3v3 teams) are so strong right now. Insane burst potential aside, retribution paladins offer a variety of utility with their hands, cleanses, stuns, and backup heals, however, I feel their biggest selling point right now is their endless resource bar as well as providing their mana-user teammates with a near-endless source of mana, as well. WOW POWER LEVELING is not an easy job.

Replenishment was originally implemented at 0.5% mana per second back in WotLK beta but was soon deemed too powerful because it would scale too well with gear and such. Even at the current 0.25% mana right now, you are looking at 1% total mana gained every 4 seconds just from Replenishment, not even counting the players own base mp5/regen. When you consider that retribution paladins and survival hunters can effectively keep this buff up on their entire team for the whole game basically, you can see how much of advantage this offers these comps, especially now moving into season 6 about WOW POWER LEVELING.

Because of the rise of resilience and stamina on gear, the need to gem for survivability will decrease and thus allow for gemming for longevity, aka gemming intellect. This is something I expect to see much more of this season with any team that runs a Replenishment class. With the right gemming, a priest can easily reach the point where they gain over 60 mana per second from Replenishment alone in full PvP gear. Let us then say, for example, you are running a Holyplay comp where you also have access to both Blessing of Wisdom (91mp5), Blessing of Kings, and/or Mana Spring Totem (also 91mp5), you are looking at around 391 mana gained every 5 seconds on top of whatever base regen they have, which is usually around 150 to 200. 600 mana every 5 seconds? Can a priest even spend mana that fast?

Anyways, I am honestly not sure of a good fix for this to balance the mechanic for arena but not hurt Blizzard precious PvE aspect of the game, but maybe something along the lines of having Replenishment instead increase the overall mp5 rate of the caster by 25% or so would be more fair at this point. Looking for any suggestions on this, as well.

Update: Replenishment was hotfixed today WOW POWER LEVELING.

We are making a hotfix (any minute now probably) so that Replenishment in arenas will only affect the character and not the whole team. It will continue to function as it does currently outside of arenas. We feel Replenishment is balanced for larger groups, but just makes too much of a difference on smaller arena teams. Making the rules work differently in PvP and PvE is not a solution we like to use often, but in this case we think it fixes the issue cleanly, while still making the talents in question useful to the character who takes them. Alternatives, such as nerfing the amount returned by Replenishment in arena or making it not function at all, seem like more punitive choices from which we want to stay away.