For all those critics with Tier 1 builds: It's a Fortitude save, not a Will save. Not that this helps much. Yes, Artificer, Cleric and the others will win. But this is a build that is different, while remaining competitive with challenges well above its CR.
On amending the Commandment: The beauty is that I don't even have a multiplied effect. It's just that you can't hit with both an axe and a hammer with one weapon (short of extreme Aptitude cheese), and the save is abusable enough that it's worth it.