Nobody can tell how scarce source points will be in the final version. During one of the patches they removed most of the source sources without any replacements, so they are probably more scarce than they will be.
But at the current state the general idea about source it, that nobody really likes how it works now.
Like here:
http://larian.com/forums/ubbthreads.php?ubb=showflat&Number=600856#Post600856 Right that touches on a problem I have with it which is - the game is meant to be strategical. On any non-easy difficulty you have to be smart about how you use your resources. That's fine, but also closing off the fun abilities from "cautious" players doesn't seem like the right move. Personally I would hoard any I got because of a potential quest or exploration that needed one to complete.
