As it has been stated, the stock IRs were shot too short to be useful for UltraRes. Remember, folks, that this advancement was really not foreseen by anybody at FAS and was really done on a whim after impulse response capture started getting more advanced - pretty much because of Kevin at Ownhammer and also FAS studio sessions. I can't remember which came first though - chicken or the egg stuff at this point.
There are loads of people who use the stock IRs, and for that reason alone I can't see FAS going back and shooting all of the IRs over again. Additionally, it looks like the redwirez IRs are too short to be effective as UltraRes IRs and there's nothing that Fractal can do about it. So I imagine that even IF they do release some of the stock IRs as UltraRes, if you won't have to outright pay for them they'll still be optional to be loaded in user slots. Perhaps with the Axe-fx II XL coming out, part of the incentive will be additional factory slots that come prepped with UltraRes files, but aren't we at a maximum for factory cab slots in the Axe-fx II (regular) at this point now?