[Kameron8]

People would probably complain about race metagaming and I don't think making it a toggle is really a good idea.

I don't think this is much of an issue among the more obvious races. Very few people encounter this issue with Shaitans, Kaelensians, etc, because their racial features are very defining. What you describe is primarily only an issue for Vampires, since 'race metagaming' amounts to enchanting a weapon with holy for a rather extreme bonus. While people could theoretically do the same to Umbrals with light damage, it isn't as if they wouldn't fade out at night time from a roleplaying standpoint anyway.

Can you expand on why you don't like the idea of making it a toggle?