^You're right, it doesn't matter at all. John Cho is Korean, George Takei is Japanese. Zachary Quinto is Italian, Leonard Nimoy is Russian. Zoe Saldana is part-Latina and significantly lighter-skinned than Nichelle Nichols. Chris Pine, Karl Urban, and Simon Pegg all have different eye colors than their predecessors in the roles.
Laila Rouass is actually Indian/Moroccan, while Sirtis is Anglo-Greek. So they're both of half-Mediterranean derivation. And I do think the resemblance is much more than just "a bit." It's as strong a resemblance as Quinto and Nimoy, if you ask me.