I'll share my stats here since I got an admit... I think it supports your hypothesis of them trying to build a diverse class.
Canadian / Age 26 / GMAT 710 / GPA 3.6 / 4 years WE
^ that in itself is pretty average as far as most applicants.
But then you add in: railroading in one of the harshest winter climates in the world (you'd be surprised how little things have changed from a century ago... I've been out there with simple hand tools hammering spikes), international work experience, and the ability to communicate in English/French/Chinese/Spanish. Heck, in the "list your hobbies" section, I even risked telling them about how much I enjoy attending fashion shows. It probably could have worked against me, but I told myself that if they couldn't appreciate the side of me that's drawn to creativity, then I don't belong there and the ding benefits the both of us.
Anyway, I 'm not sure how the waitlist works, but if you think you're on it because there are too many admits that already share your profile, perhaps the strategy is to push the diversity front with adcom? Might as well give it a shot... not much to lose at this point.
I'll be rooting for you guys!