It would do best in the specialty category, because that's what it is. And I feel Oat stouts are separate because the oats change the beer in the mouthfeel and head retention, as well as flavor to a certain extent. in Black IPA's all you get is a color change.
Dort Export is named from the region it was developed in and was a different beer than the others, I assume. If you expand Pils to include Dorts then you are muddling the Pils cat because those beers are different enough that you can tell without having to look at them. Again, the major diff between IPA's and a Black IPA is the color. Is that really enough to warrant it's own style?
When you say "overt roastiness", are you talking about these Black IPA's? Because my understanding is the roastiness is low to none. And there are plenty of IPA's that have low maltiness to med maltiness that are still IPAs, so I think that argument is out the window, too.
So the main differences between an IPA and a BIPA are the color and a hint of roastiness ... how does that transcend into a new category? I just don't see it.
If everyone started brewing oat stouts with a low SG and with the addition of special B, would that be a different beer or still be an oatmeal stout?


