I was thinking about this some more.
This really had only one reason to be added :
Life and Death doesn't get nodes.
So archangels and demon lords are their "nodes", where the source of power originates for the realms.
This still holds true in a flavor sense, so the ability is justified for that reason.
However for gameplay, not so much. First of all, Chaos/Nature/Sorcery mastery is gone, so realms no longer benefit from having nodes of their own realm at all anymore. Second, realms are fairly evenly matched in producing late game power. Life gets Life Force, Sorcery gets Uranus' Blessing, Nature gets Seismic Mastery, Death gets Dark Rituals and Chaos has Armageddon as their primary power production spell. So there is no reason for Life and Death to have an additional one. But this is for the human. For the AI, the AI with Life is generally underpowered. Death, not so much, but it's still less of a threat than Chaos, Nature or Sorcery.
So...if we want to keep the ability for flavor, but on gameplay only provide some benefits for the AI, not really for the human, then the answer is, add maintenance to the units. With a maintenance of X, and below X power generated, the unit stops being a net power producer (although it still allows reallocating some MP into SP or RP) while the AI with the maintenance discount still gets to use the units as power sources.
So..I think a good solution is to make the units have a maintenance of 18 but keep the 12 power production. This makes the unit cost an effective 6 mana only.
This really had only one reason to be added :
Life and Death doesn't get nodes.
So archangels and demon lords are their "nodes", where the source of power originates for the realms.
This still holds true in a flavor sense, so the ability is justified for that reason.
However for gameplay, not so much. First of all, Chaos/Nature/Sorcery mastery is gone, so realms no longer benefit from having nodes of their own realm at all anymore. Second, realms are fairly evenly matched in producing late game power. Life gets Life Force, Sorcery gets Uranus' Blessing, Nature gets Seismic Mastery, Death gets Dark Rituals and Chaos has Armageddon as their primary power production spell. So there is no reason for Life and Death to have an additional one. But this is for the human. For the AI, the AI with Life is generally underpowered. Death, not so much, but it's still less of a threat than Chaos, Nature or Sorcery.
So...if we want to keep the ability for flavor, but on gameplay only provide some benefits for the AI, not really for the human, then the answer is, add maintenance to the units. With a maintenance of X, and below X power generated, the unit stops being a net power producer (although it still allows reallocating some MP into SP or RP) while the AI with the maintenance discount still gets to use the units as power sources.
So..I think a good solution is to make the units have a maintenance of 18 but keep the 12 power production. This makes the unit cost an effective 6 mana only.