I do agree with Empath, in keeping it simple. Perhaps, in addition to making Raiments, Elemental crystals could be used to craft weapons and the like, in a system where more advanced weapons would cost more crystals to forge. (ex., A plasma caster would cost four crystals, but a handgun would cost just one.)
I dunno. In hindsight, this might be more complicated than need be, and probably not the feel you were going for. 
Supposing this idea is as off as it sounds to me now, I would suggest keep it simple, much like your first post on the matter, Gisk. Perhaps 30 crystals for Knights and Monks, and 15-20 for Ascendants? (Those numbers just came from the top of my head, actual numbers would warrant a bit more discussion. The crystals would, in turn, let you make your Raiments in some varying degree of badassery. Then perhaps leftover crystals could be converted into hypothetical 'skill points, to be put into skill trees. (Which I would be more than happy to help make.)