Researching spell is counterproductive

[IKerensky]

I mafe some funny solo game Last night with a 'live' ermor with the Prince of Death pretender. I got to unholy magical level ( all at 4, astral 7 and death 14 ) and researched the full library then I start to notice something:

When I only mastered Conjuration, Construction and Evocation I won all the battle easily, turning the ennemy armies in cinder.

I started alteration and my mages start adding some stupid buff spells at the end of their script.

But when I researched Enchantment and Thaumaturgy then they really really become crippled, keeping buffing them and any other unit or chain casting various summon undeads... ( always the low level one of course , and forgetting to drain life some time when fatigue was high, nor relief neither... ).

Basically my Pretender could easily crash several ennemies by casting only direct damage or area damage spells, but when he finish his script he ressort to stupidly low level spells and methods ( 2-3 shield then chain skelettons ), even when not alone... I think that is a pretty unefficient way to bog a 14th levle of Death

I start to think about entirely skipping whole spells schools to improve the AI, is it a good idea ? if so wich one ? Enchantment seems obvious but Alteration and Thaumaturgy have niceties in them