So much so that if a character is just "determined" enough, he or she can resist shielding attempts by sa'angreal wielding foes, or handle a running battle against entire circles of linked channelers etc.
Basically, if your need or desperation is great enough, you can launch dramatic ripostes against vastly overwhelming strength levels to drag out a fight until an advantage opens up to you.
This is in no way similar to the Cyndane situation at the Cleansing, where only vastly superior skill, knowledge and precision allowed Cyndane to resist Alivia's angreal enhanced strength.
The examples from aMoL are numerous, but essentially, various characters - on both sides of the Light/Shadow spectrum - survive vastly overpowering Power assaults simply through desperate last minute "parries" or sheer, bloody minded determination not to be shielded.
It is so jarring that it makes a mockery of the entire book. By his logic, Sorilea should be able to resist being shielded by Moghedien, simply because of her willpower.
He really has no concept, has he.
I had a mini-theory suggesting that strength and OP limitations had more to do with a block than anything else, so most channeler's limits have more to do with not needing to risk losing control as they clearly can exceed the amount that is safe for them to tap into - part of the initial lessons learned during the Novice years is how dangerously easy it can be to exceed your safe limits.