So far, the only weak point for me is half of the power of my Artifact being tied into random dungeon drops. I'd have prefered it it was something I could just work on and know, if I work hard enough I can max it out...eventually.
But as it is now, it's the same old RNG that can screw you over if the slot things don't drop (or one drops that doesn't help you/for a slot that's already filled).
It kind of makes me wonder, if I have to get a drop to increase the item level...why not just drop a weapon? Because that's basically what it is