I understand it from the logical point of view, since anything revolving around undeath is hardly natural, so we get magic requirements for this tree, but
It's a category point AND lots of wasted stat potential for a tree, which, while flavorful, doesn't seem to be excessively powerful to me.
So since wyrmics get absolutely no benefit from magic stat, I would suggest giving the first sustain also the ability to convert it into something useful, like turning spellpower into mindpower/crit/dmgpen or anything, really.
So, what do you guys think? Are you fine with the said tree being "as is" or do you think it would be fair to tweak it with some kind of magic-stat synergy?