A couple weeks ago someone suggested that Druids require access to a Nature node in order to learn all them nifty Nature-based spells. I posted in to second that requirement. I also added a suggestion that rule should extend to all units that have an ability to cast spells. But at teh time I could not rememebr my rationale for such a change.
Well, much to your chagrin I have remembered the rationale.
1) One reason to make such a change is sort of 'makes sense' for spell casting units to all folow the same rules. But 'makes sense' isn't good enough a reason.
2) A better reason is that certain magic use affects diplomatic relations. Well, it's more accurate to say that certain magics are
supposed to affect diplomatic relations. Sometimes they do, sometimes they don't.
If you are playing Ljosalfar and decide to build some Contagion-casting mages, you will need a Death Mana node. Building this node will earn you a major diplomatic negative with certain civilizations.
But if you are Calabim and you have developed Vampire technology, then you can create dozens of Contagion casting units and no civilization in the world will object. This is because Vampires do not need a Death Mana node in order to cast Death magic. Ditto for Ashen Veil and their Death-casting, Entropy-casting Priests.
3) Adding a node requirement for all units will admittedly affect a large numberof units. The largest effect however would be to make Desciple units especially Priests a tad less valuable. This in turn makes No State Religion games a bit mroe viable. I've recently played some extremely fun games without relying upon a state religion for long, long stretches. Since civilizations can thrive with no state religion, this leads me to believe the designers can reduce the "Religion Goodie Basket" by a caramel apple, and still leave religions as powerful forces to be reconed with in FfH. So it seems to me that if a religion wants to dabble in the Dark Arts, thar religion should, at least, earn the same international pariah status as secular dabblers in teh exact same Dark Arts.
4) Note that the node requirement would not actually inhibit players very much. Most religion's Holy City building prvides the core mana node type. 98.8673% of all startup maps offer at least one raw mana node within each civilizations' startup zone. The primary effect would be to ensure diplomatic penalties would apply if a civilization actually
used the abhorred magic type.
Inventing Ashen Veil would not trigger the diplomatic effect. Building a Death and/or an Entropy node so the AV Priests could actually begin casting those spells would trigger the diplmatic penalties. Thus it would be possible to invent AV, or create a Death-casting hero, and avoid the diplomatic hit by delaying node construction.
Submitted for consideration FWIW.