Pretty solid, maybe a touch underpowered.

I've been wondering lately about whether Holy could be included in It Is What It Is.

I don't see why you couldn't. I mean a sword of the cross has the attribute Holy but if you took that away you can't get away from the fact that it is a Holy weapon. Even if you took away the spiritual and magical forces behind it, the sword would still be an item with a relic that would be considered Holy to any one of church faith. That alone would give it enough power to be Holy