When Warlock was introduced there were 3 pacts, Fey, Fiend, GOO. we now have Abyss, Celestial and Carceri. so the problem is that aspects of Shining through only work partially for Abyss Pact. See Below
(Yet another flaw in this pact that i want to like but have a hard time doing cuz it's been ganked since release.)
I want to focus specifically on the flaw of Shining Through, how to fix it and not necessarily what work arounds there might be for healing amp currently in the game.
Shining Through: Gain a Sacred bonus to Temporary Hitpoints equal to 8x your Constitution Score that lasts for up to 10 minutes. For 20 seconds, you gain +25 Sacred bonus to Healing Amplification. (Cooldown: 30 sec. SP Cost: 8).
So this means that 2 things,
1) Warforged warlocks only gain a 5% net gain IF the player has taken Repair systems: Healers friend in the racial tree. However, for a Bladeforged, which has a net 60% penalty to incoming Positive healing actually loses out on any benefit to healing amp and would still be at a -5% net loss after casting Shining Through. Granting that yes there are other ways to heal as a BF with the Communion of Scribing SLA: Reconstruct.
2) Abyss Pact warlocks get minimal benefit from the bonus to POSITIVE healing amp if they choose to be undead with the channel the abyss feat granted at 15, which is one of the main points of doing Abyss Pact. Granted that yes an abyss pact warlock does receive positive heals but has no way to reduce the 50% penalty as with WF/BF racial trees. so if a abyss lock is self healing with death aura this benefit to Positive Heal Amp is a nonfactor. They would only get a small minimal benefit if they have a healbot hireling following them.
TBH earlier this spring i ran up a first life abyss lock from level 7 to 30. Once i had channel the abyss i quit using hirelings to heal me as death aura took care of most everything.
Solution
Simple Solution: Add in Negative and Repair Healing amp to the enhancement. This simply covers all the bases for any type of build whether Pure 20 warlock abyss pact or a BF ES build, or some other hybrid multiclass build wanting to use Shining Through. it also brings it up to current standards. It worked perfectly fine when there were only 3 pacts but adding in the Abyss pact added in an additional dynamic that wasnt address (or maybe it was and then was ignored during Lamm testing?) during the rushed development and release of the new pacts. That's not a dig at the Dev team that's just a simple truth. the new pacts were rushed and could have used a couple more weeks in development to work out a few things. that not just my opinion that's been said by a lot of folks. Anyways...
even with this statement "Although the fiendish origins of some warlocks' powers can’t be denied, not all Warlocks embrace the darkness. Some turn toward the light. Such rare individuals are called Enlightened Spirits." why should certain body types be left out? Thematically i understand it. However, maybe the only way for my character to redeem itself for the evil things it did while alive was to make a pact with an abyssal being and then use the ES tree as a redeeming factor. or maybe I am a _____ Pact warlock BF that is atoning for war crimes during the last war and to atone for those deeds i am using the ES tree to "do good."
Advanced Solution: although this solution may require more overall work it actually simplifies the game as a whole (beyond the Shining Through problem.)
This solution/proposal possibly needs its own thread.
REMOVE Positive, negative and repair healing amp REPLACE these with Global Healing Amp. or possibly just calling it healing amp. My first thought was to call it Universal Healing Amp but that may be confused with how USP works to provide "X Amount" of power to each spell power. What I am proposing is to roll all 3 types of heal amp into 1. Yes this would require overhauls to gear, cannith crafting, spells, some AP trees, and filigrees. However, it levels the playing field, at least to a point. I haven't worked out every last detail of this solution but it could serve as a starting point.
I didn't do a deep dive research session on this but going to some dnd 3.5 and 5e sources on WF, PM and Abyss warlocks i was unable to find anything listing penalties to incoming heals. Healing penalties are like saying that my Abyss lock can't be on the cover of Dungeons & Dragons Illustrated because she's undead. It's re-tarded. So after researching this it indicates to me that healing penalties are a DDO thing which needs to go the way of the dinosaurs. you can still quantify certain spells to affect only certain body types such as repair types for WF/BF and negative types for undead.
Bottom Line: Alter Shining through so each pact has benefit from it!