My experience with low WE tells me that if the player doesn't already have high cores, it's best not to waste your time.
I signed one player 2 seasons ago who had a WE of 18. Now as a junior his WE is up to 25 (because he's started from Day One), and meanwhile he's gained 66 points of ratings overall in those 2 seasons while other players with higher WE have gained 80-150 their first 2 seasons. Some of that is no doubt also related to potentials but higher WE also helps with how quickly they learn your sets (off/def IQ), and from what I've seen it even helps with grades.
You'd think I would learn from that, but my current freshman class includes 3 guys with WE under 30 because I liked their cores/potential better than my other choices.