It's more that it's difficult to truly eradicate culture when the majority of the empire is so very far away, but the Empress I work for is entirely in favor of allowing recent acquisitions (as in the last 600 years) their traditions (the very fact that she's a woman irritates everyone anyway, so she might as well go for radical progressivism).
I know we've chatted about this before, but how many worlds have you been to, again?