10% is 10%, it's not gonna break us but it is a hell of a nerf. Although initially it still appears that, on the beacon at least, Divine Light will still have greater HPM than Holy Shock.
Using (very) rough math based on the tooltips from wowhead,
DL = 391.1 Healing per % of base mana
HS = 342.25 Healing per % of base mana
A 10% nerf to DL brings its number down to 351.99. Add in its higher spellpower coefficient and the rest of the math you geniuses are all better than me at and DL is still a more mana efficient way to heal your beaconed tank.
With Holy Light and Flash of Light also being nerfed, Holy Shock on cooldown will be even more important.
There was also a hotfix to Walk in the Light, reducing it from 15% to 10%, which is already applied on live. I don't think this has been announced yet, and I only noticed while confirming my new spreadsheet.
Can this be confirmed?
Also, are these nerfs possibly a precursor to fixing the talent Conviction?
Right, kind of. We discovered that Conviction (which can give up to a 9% healing bonus) was broken. It affected paladin self heals, but not healing other targets. Since we think that paladin healing throughput is in an overall good place we didn't want a 9% bonus sticking around. So we fixed Conviction and reduced the Holy passive, Walk in the Light, from 15% to 10%. Which actually does end up with a net 4% gain overall, assuming Conviction has near 100% uptime, which isn't too unreasonable.
Since it was applied in a hotfix the Walk in the Light tooltip won't be updated until 4.0.6
Looks like the mana costs data-mined from the PTR are slightly different that the advertised ones from Blizzard:
Originally Posted by MMO-Champion
# Divine Light now costs 33% of base mana, up from 30% of base mana.
# Flash of Light now costs 30% of base mana, up from 27% of base mana.
# Holy Light now costs 10% of base mana, up from 9% of base mana.
Maybe Blizzard relented on the 10% across the board increase? Also looks like the official PTR notes (Public Test Realm Patch 4.0.6 Notes - Updated Jan. 24 - World of Warcraft) have been changed to say "approximately" 10%. (Atleast I don't think they said that before)
Those datamined spell costs ARE a 10% across the board increase for the single target spell costs, with rounding.
Your increase math is a bit off as well. From the OP: Healing Modifier Stacking = Heal * (Spec + SoI + Crusade) * WoG Glyph * Divinity * AW * DP * Conviction. Accounting for Walk in the Light, SoI, Divinity, and Conviction our healing multiplier was (1.15 + .05) * 1.06 = 1.272 before either fix and (1.1 + .05) * 1.06 * 1.09 = 1.32781 after both fixes. That's a net increase of 1.32781/1.272 - 1 = 4.46%.
4.46% more healing for 10% more mana comes out to (100% + 4.46%) / (100% + 10%) = 95% of previous mana efficiency. So basically 5% decrease in efficiency for HL/FoL/DL, but 5% increase in healing across the board. I'm not sure I'd even call that a nerf, it seems to be mostly a lateral change just as the blues indicate.
Good news, Walk in the Light is almost a completely useless passive. Down to 5%. At this rate of a nerf every 2 days, maybe priests will only be able to pull triple our heals per second while getting buffed.
On a similar note, does blizzard even look at world of logs? Top healers for EVERY fight are priests with a few paladins yet every healer except us is getting buffed, what gives? Has Blizzard given any logic or evidence to defend this change? I don't care how you look at it, 10% mana cost increase and ~10% healing decrease is going to add up.
I am fairly certain that's a typo in the hotfix notes, and they meant reduced by 5%, rather than to 5%. Otherwise, it wouldn't be a net healing buff with the 9% conviction fix. For the record, this is what the current hotfix notes say:
* The bonus healing provided by Conviction now functions correctly when healing other players.
* The passive healing bonus from Walk in the Light has been reduced to 5%, down from 15%. This change is to balance against the fix to Conviction, but still results in a small overall buff to paladin healing.
Anyway, I predict (assuming it isn't a typo), it will only be around a 0.5 to 1.5% nerf, depending on the person's usage of Holy Shock.
Due to the way our multipliers work, as far as I can tell - this is a BUFF to Holy Shock, assuming you have Crusade. To all other spells it is a very tiny nerf, except for PotI, in which case it is a small nerf.
PotI, since it was a self-heal, was never bugged with Conviction, so it takes the nerf without any compenstation, which is probably fine with Blizzard since they already saw a problem with PotI.
I am fairly certain that's a typo in the hotfix notes, and they meant reduced by 5%, rather than to 5%. Otherwise, it wouldn't be a net healing buff with the 9% conviction fix.
Yes I would also think it is a typo due to they said we should still get a minor buff, which is the talked about 4% increase that the blues said. However, if it were not a typo, then it is indeed a very small nerf. I couldn't really say from last nights encounters that I felt this nerf. I think at the moment, I won't feel it until the patch, even then I think the newer Paladins will feel this more so than the veteran.