Whenever you level up and choose a new ability or spell for your character, a bar above that particular "school" goes up (ie. Creation/Primal/Spirit/Entropy for mages, Two Weapons, Sword and Shield, etc. for fighters). Is there any special bonus you get for maxing out the bar and getting every ability in a given school?
In other words, am I better off focusing my abilities in one school, or in getting some abilities from every school?