I think it would be a great feature to not only test/measure your speakers but to also actually test/measure your ears!
I know that I 'lost' some higher frequencies playing drums without proper protection for my ears when I was young (and yeah, really naive and stupid). I even have the printed curve from my last test at the ear specialist. It's subtle, but it's there. So I'm used to actively taking this into account and compensating for it when I'm mixing.
So for me it would be just plain awesome if some sort of hearing test were implemented into Reference 3 that in turn takes your individual hearing profile into account as well when adjusting the sound...!