As I understand it, the SK fragments by themselves don't inherently grant nor possess Reality Warping or fate altering abilities. The Hōgyoku does.
Aizen and Kisuke reached these abilities through their own ingenuity. The SK fragment in this case seems, to me at least, like nothing more than a power source.
For instance, if we had a generic genius scientist character who devised some insane Supergenius level technology, but achieved said tech with the help of an outside energy source, I don't see how that would invalidate the intelligence feat.
Likewise, them initially failing to perfect the Hōgyoku doesn't mean much. Again, circling back to generic scientist-kun for a sec, if a character fails to achieve some insane SG-qualifying technology, but had to go through an arduous trail and error process to get there, they'd still be a SG. Not only is it a very common trope for scientists, it's also a thing IRL. Science is all about trial and error. We rarely get things right the first time, and this goes for even the most ingenious among us.
So, yeah, all in all, I'm in the same boat as Tracer.