That was a tough (nasty?) room to record in... Sometimes the most detailed gear suffers in bad rooms and actually sounds worse. Much like the detail of the v3 can be too much in those situations.
Again, we've seen where the v3 > r09 was preferred over the v3 a/d. And that was in a very good room. Shocking, but true. Would we have preferred the r09 over the mytek?
I think it takes quite a few recordings to appreciate the character of gear. So no way would I discount the mytek at all from this comp.
Your more recent comp where you mention using the splitter... With -18db into the mr1. I'd be somewhat concerned about how that may impact the overall impedance and signal. If you put an attenuator on one side of a simple splitter, I think it must impact the overall impedance going to the other side of the splitter.
I've never seen any tests where anyone analyzed the sound quality of the mr1 at different gain settings. It may have trouble areas, much like the r09, r09hr, and others.
And transformer smearing of transients.. It does depend somewhat on the transformers. The higher the ratio, the worse the transformer specs, and the less the bandwidth. And probably, the more they lose detail. The most expensive, no-compromise *transparent* transformer preamps use low ratio transformers (typically 1:2 jensens, the jt-16's). The psp2 uses 1:10 ratio custom transformers. My AERCO has 1:1 Reichenbach's. I love my aerco, and it is extremely detailed. But there have been times when I've chosen it over the v3 for stage lip recordings and felt I lost a little transient detail.
In some ways, transformers help us regain that classic analog sound and reduce the digital harshness. They may also reward us psychoacoustically, giving sound character that our brains grew up with. Especially those who grew up in the analog era.