I have definitely noticed issues with resists, in all though it seems to boil down to these points:
1. It does not seem to matter how much disruption, subjugation, etc you have...if the mob is anything above even con it gains considerable resistability even with an excess of 600 - 700+ casting skill and all masters.
2. It doesn't seem to matter if you throw on your noxious debuff, even with enhancements to its debuff value your spells will not gain much of a higher hit-rate, adn will still be mitigated and deal low damage, but all of a sudden when brigand and other debuffs land your spells suddenlly hit far, far harder and nearly never get resisted.