Instead of weakening Companions, why not strengthen the hedge wizards instead? Makes for less headaches.
A simple way of doing this without being over-powered is to give the Gifted Companions 1 Minor Virtue + (1 Major Virtue or 3 Minor Virtues) + (1 Major Flaw or 3 Minor Flaws) much like an Ex Miscellenea.
I.e. 1 Minor Virtue and up to 13 V&F (as opposed to 10)