The Breton 50% resistance to magic does not nullify the Apprentice 100% weakness to magic; rather it halves it, producing a character with 50% weakness to magic.
Since it appears Count Lauriel's intent is to play a Breton that is more vulnerable than normal, this solution accomplishes that nicely.
While the Altmer Apprentice may be considered as good stock for the ultimate glass cannon, a Breton Apprentice is an enjoyably fragile character, if that is what one seeks.

Actually it does. the way magic resist and weakness work it does completely nulify it ,at least in my experience since the effects don't cancel each other ,because positive spells like resist or spell absorb are checked first and negative effects are checked after those effects
So say a mage casts a damage health 100 spell on my Breton Apprentice ,the game first checks my magic resist halving the damage to 50 ,it then checks the Weakness which doubles it to 100
I think it should change so that it just takes away 50 percent to weakness