It's a cool feat, but hopefully a reasonable DM wouldn't require you to take it. Perhaps add an additional mechanic benefit i.e. you gain one or two alignment subtypes of your choice (so your weapons count as that alignment for overcoming DR, and you count as that alignment for the purpose of holy word, protection from chaos, etc.)? Or instead of a specific alignment, "for all effects related to alignment, you count as whatever alignment would be most beneficial to you at the time".