To me, this is a huge quality of life change requiring little developer labor. I'm suggesting that the health bars displayed for pale masters in undead form and warforged/bladeforged party members have a different color than the standard red. I'd suggest purple health bars for pale masters in undead form and silver health bars for warforged/bladeforged. Fleshie artificers with the construct essence feat could have a grey color or just stick with the standard red since they still receive larger heals from positive energy than from repair spells. For the very few forged characters who take the improved fortification feat that makes them immune to positive healing, maybe they could be assigned a very, very dark grey colored hp bar.
This would solve a number of continuous problems for many builds while in parties:
1) Benefits to Healers healing the Fleshie and Undead: Healers in a party/raid group won't be wasting spell points misguidedly casting positive energy healing spells on wizards while having no idea whether or not they're pale masters and totally immune to positive energy. And, divines would have to consider carrying the Harm spell and they would actually know for sure which party wizards would benefit from it just by looking at the party UI.
2) Benefits to Fleshie Wizards: Fleshie, non-pale master wizards would receive third-party heals since healers won't assume, based on their wizard icon, that they're immune to positive energy heals or don't need heals since they're probably self-healing war-/blade-forged.
3) Benefits to Positive Energy Healers healing the -Forged: Healers in a party/raid group will be able to see those war-/blade-forged in the group who will likely receive smaller heals from positive energy and be able to adjust the strength of their choice of healing spells accordingly. And, healers will see silver/grey hp bars next to an arcane/artificer icon and consequently know that they can self-heal through most things and don't need as much help.
4) Benefits to Repair Healers: Classes with access to repair spells will be able to see whom those spells will affect just by looking at the party UI. Artificers, who are not a competitive class at all right now, have access to both positive and repair healing spells and admixtures and this simple UI color change of health bars would increase their effectiveness in groups by knowing who they can most effectively heal with what repair spell/positive energy admixture by looking at hp bars.
5) Overall Benefit of Less Healing Confusion: A significant amount of the balance problems with 'non-self-healing' builds would be ameliorated and some problems with healing classes being 'less fun' would be ameliorated by this improvement of their efficiency (and how transparent and enjoyable healing is) by far.
This is a simple change of the display of colors in the UI that, I think, would improve the balance of classes greatly without 'nerfing' or 'buffing' a single numeric value. It would require no additional 3d graphics, animations, nothing like that. Just a change of colors, resulting in a large quality of life improvement.
I rest my case. Please provide opinions and "/signed"'s or "/not signed"'s.
EDIT: As some people replying to the thread have pointed out, the colors of hp bars would need to change under some varying circumstances. For example, war-/blade-forged sorcerers in the capstone savant elemental forms become just like fleshies in terms of their receptiveness to positive energy heals and being immune to repair heals; so their hp bar color would need to turn to the standard red in those elemental forms. The same thing would happen with characters with druid levels going into animal forms. Dead characters raised through the tier 5 pale master animate ally enhancement or by the Cursed Blade of Jack Jibbers would need their hp bars turned purple (which should be automatic since undead forms would already be coded as turning to purple hp bars under this proposal).