I don't know how much it does for immersion since this is the first time we're hearing mention of genies in any context, but I agree that it's probably just a throw away joke.

As for what I want to know before release; any major systems changes, what companions we're going to have (at least the ones we'll meet by the end of act 1) and confirmationon whether or not Tav is going to have any sort of special backstory.