The ability to mod swap isn't really a valid argument to me here.
Is your hair a bird?
Take WP augments = Have higher crit chance from WP = Need less crit rating = Replace mods with crit rating for mods with power = Have more power. Simples.
It also doesn't matter massively where you change your stats, be it a crystal, mod or an enhancement. And 40% is indeed absolute recommended maximum for a Sage healer.