Just throwing this concept out here

[PvK]

Sounds reasonable to me.

[Endoperez]

I, on the other hand, don't see the need for this change. There's no good and no evil, per se. Nature can cancel Death, and Death Nature. I'd rather see these aspects that can cancel other paths made into new spells, than make some path combinations rarer or more expensive. Rain makes Water good against Fire in the early game. I'd rather like to see THAT kind of opposition. Fire Ward and Fire Fend, from Fire and Water, Frost Ward and Frost Fend, from Water and Fire, etc.

[B0rsuk]

And I don't like the idea. Not just because it's s cliche. I prefer when school strenghts come from gameplay mechanics, and not from artificial bonuses. Besides, there are some spells with odd path combinations, like acid spells (fire + water, nature + death ). They are possible because no two schools - so far - are directly opposite to each other. Nothing is set in stone.
Anyway, spells designed to fight certain paths already exist, even if they're not very numerous. Kindly Ones, Maggots, Cleansing Water, Inner Fire, Purgatory, Astral Corruption, Rain; spells that affect climate upset either fire or water mages. Wind Ride is ineffective against Earth mages. Lots of suble and less subtle effects.

[alexti]

I think that it may be more interesting to counter-position national/non-national magic paths rather than some predetermined pairs. Basically, national magic paths would be cheaper for pretender and other paths more expensive. Thus, for example, for Vanheim air magic on pretender would cost significantly less than fire magic. This would help to keep national magic more different in the late game by making it more expensive to get into other paths through pretender...

[B0rsuk]

Alexti: Magic available for nations already become much more specific, because independent mages are much worse now. On top of it national mages of the same quality cost much less.
Discouraging using strange paths on pretenders would narrow available spells even further. Pretender magic is - for many nations - the only way to try something new. And you're pretty much required to have national Blood mages if you're to try blood magic at all. And it would harm bless strategies, too. Kailasa sacreds, for example, literally scream for Air bless, because they have little to no protection. But none of their mages has Air,even as random. Should they be denied a chance to try air bless ?
I think it's enough that pretender choice strongly depends on the nation. It makes some paths pretty hard to get, unless you try human pretender like archmage.

[UninspiredName]

B0rsuk, I see what you mean. That was partly why I wanted the cost-boost to be so low. Keep ind mind that most fire/water or death/nature things you see only require one or two levels in a 'secondary' path, which is still mighty doable with the suggested penalties. (I also like the 'opposite synergy' spells, and at this point can hardly play Pangaea anymore without Carrion Woods/summons) Though a very large chunk of the anti-path spells you named are against undead and demons, which, using a lot of Blood magic and a good chunk of Death, is a pet peeve of mine. And Astral corruption isn't so much against a different path as it is for blood. Like saying the various spells that boost the level of astral mages are designed for anti-non-astral purposes.

And I strongly disagree with aligning the magic preferences of a pretender with their nation any more than they are already. Especially with Independent mages weak as they are.

[alexti]

@BOrsuk: in the current state, late game plays pretty similarly, no matter whan nation you've started with. It would be nice to have more nation-specific late game. Increasing costs of non-nation paths would make such setups more expensive and made an option of trying to do with limited set of paths more attractive (I don't think this approach is practical in longer MP now). Making dual-9 cost more would be a good thing too (though proposed system would still made it easy to take insane blesses with Mictlan).