Okay, I forced some time to pick up the guitar this morning. Sorry
@FractalAudio for not looking into it further before posting, but thanks again for checking it out. I think it may be Cygnus X-3. I realized that I hadn't even used the SM7 since the modeling update, and I am finding that the SM7 is accentuating different frequencies from the amps; well of course it's not the mic frequency response that's different, it's the amps!
There are some positions that sounds astounding similar, but all you have to do is move the mic position somewhat and you'll hear the difference. Something about the new modelling improvements seem to agree more with the SM7 to my ears and not to make it as finicky with my guitar.
And of course, I didn't think simply to open the align tab of the cab block to view the IRs and compare visually at the same spot. Just switching between them on the front panel while viewing them in Axe-Edit made the differences plain.
This also brings home a good point about amp updates. Not only will amps sound and react differently, mics' and speakers' relationship to the amps will be different, so if there were amps, cabs, and/or speakers you avoided before, or only used in specific ways, reassess your assumptions, because you may find greater utility in what you previously ignored.