It also my biggest issue with the source system. In the first game everyone could use those 'source skills'. That the main chars were chosen demigods or what ever doesn't help with the issue, because enemies could use those 'source skills' as well.
Source management is one of the reason, I do not feel inclined to even finish the game, because it feels more bothersome than fun. Not to mention that some of those source skills are reported as pretty broken.