What I would suggest, is as follows

Vocalize

Who: all remort mage classes (archmage, illusionists, geomancers)

What: allow casting of spells even while silenced.

How: Would require a moonstone, that would basically take the place of the vocal part of the spell. If no moonstone, then the skill does not work.

Maybe add an additional % of mana cost to the spell cast this way, maybe 10% to 50%, depending on what the imms thought was approprieate.

This would make it so that silence in and of it self was not a fight swinger 100%, but I dont think would limit its usefulness.

Anyways, what does everyone think?