I find the difference between the MKI and MKII almost exactly like one (who believes) that a silver cable in the MKII was substituted for a copper cable in the MKI, exaggerated slightly (even though I know this was not the case). In other words, the MKII high end sparkles a tad more, and bass end is recessed a little more than the MKI. Depending on one's personal tastes one could say the bass is better (more emphasized) on the MKI and treble is better (more emphasized) on the MKII. OR one might say the bass is more refined (less emphasized) on the MKII and treble is more refined (less emphasized) on the MKI. So I'm not sure how to respond .... I guess I basically confirmed your assertion. If I could design my own GR07, I'd take a little of the sparkle of the high end of the MKII and add it to the MKI. I like them both, but overall, I seem to pick the MKI more often to listen to.
Interesting, that was exactly my perception of the differences as well.