I changed my post a bit, because I brainfarted while typing it.
I agree that this will have to be stellar for people to buy it over the wide variety olf excellent UWA zooms.
If it's anything like the 14mm with distortion, this lens will be useless. Even if you do fix it with an ACR profile, you'd only be left with a 12mm framing. Not that that's a bad thing, but it takes away from the advantage of being a 10mm prime.
Personally, any lack of filters in an UWA would be an immediate no-go for me. In fact, anything that's not 58mm or 77mm filter size is already at a huge disadvantage. I would hesitate to buy it if it also meant I'd have to spend $00 - 250 on a 10 stops ND, optionally 3 stops ND and a CPL.