Barbarian magic suppression skills...

For me, it all depends on who the opponent is and what bonuses are available when leveling up, and what choices are offered. Besides simply weakening spells, the skills available in these branches can also be of interest. For example, when playing against Necropolis, I will, of course, try to get Antimagic and Antisummoning at all costs. But you can also get some benefit from Antilight (it seems, what does it have to do with it?), due to Storm Wind: the key units of Necropolis – Vampires and Spirits – fly, so reducing their initiative will not hurt in any way; the same applies to playing against dwarves – here it would be good to take Fire Protection for obvious reasons. Another good trick with Antilight can be used thanks to the Daughters of Heaven. If you manage to get Secrets of Light, you can immediately hit the opponent with lightning, without sacrificing poor goblins. This doesn't always pay off, but you can find a use for it.