You make good points. However, my ears let me make my decisions. From many accounts, the Magni is on the bright side while the Asgard (and Asgard 2 most likely) is on the smoother, laid back side. I don't particularly like bright sound.
With all due caveats about comparing specifications, it seems that even after the Asgard upgrade, Magni remains a compelling offering in the Schiit lineup, particularly based on its distortion performance.
The publicly available specifications on the Asgard were more limited than the current amp lineup, as I recall, but looks like Asgard 2 delivers an order of magnitude improvement in THD to 0.008%. But that's still higher than Magni's THD of 0.005%, and Asgard 2 has higher IMD of 0.010%, compared with Magni's 0.007%. Magni's distortion specs are even superior to Mjolnir!
Where Magni comes up short is on SNR and crosstalk. Asgard 2 bests Magni's 100 dB with 102 dB, and Mjolnir delivers 104 dB. Similarly, Magni's crosstalk is -70 dB, Asgard 2 -72 dB, and Mjolnir -75 dB.
Stepping aside of evaluating the practical performance differences of a few thousandths of a percentage of distortion or 2 dB of SNR or crosstalk, it stands to reason that Magni holds its own quite well on the basic specs.