It could use about 6 more strength (or more int, but that would take a lot more). The HP loss makes it not as versatile as it should be, compared to the nord jewel of brutality.

Overall it's quite nice, just needs a little more strength (enough to add about 50-60hp) and the proc to happen on normal attacks.

BTW, could you tell us what exactly the proc does? So far I see +15 to all stats, but is there +%dmg as well? And can't tell what it does to mobs.