The source points player collect around the game around becomes memory points that can only be used to support source skills, let's say, 9 total, the player has to choose who to distribute the points among his party, this means that the source points the player collects becomes a stat instead of a consumable.
It's way too late to really implement something like that, but I quite like the idea. Basically balances every fight around the fact that you'll use 1 or 2 source skills per fight.
More realistically, I think the source skills should just be toned down slightly, and then make source points more common. Again, balance fights around the assumption players will use 1-3 source skills in most fights. This will make source skills feel powerful and important without making players feel like they need to save them for the hardest bosses. I think this may be the direction Larian is planning for given they're saying source will be more common in act 2.
