Are you thinking of making him a shadow sorcerer? I think, that would fit.
Oh yes, or at least multiclass into it, as wizard / wild magic Sorcerer is one of those odd mixtures, I very much enjoy. We'll probably have plenty of chats with Withers once the patch releases.
Bladesinging also sounds interesting, not to make the Shadow Weave felt but in general - and for the shallow reason that I like to hear Gale's dipping comments more often. ^^
