Soul Crystals and class customization

One of the things that I feel the game can improve on is allowing some variations between players, more choices. Currently the only difference we can choose is 30 points in a stat; but 90% of the time we will choose one stat. Yes, having less variables means classes are easier to balance, as that was the point of removing special effects on weapons and Artifact armor that existed in 1.0. But to this end, I feel we can add some awesome elements without being too game breaking or cookie cutter, and I think we can do that through our Soul Crystal!

Imagine a couple Job quests that can award us with more soul crystals, maybe 2 or 3 per job. They could change the function of existing skills, say increase potency or duration of a buff, or even improve the funcationality of skills.

Ideas?