I don't think it's an excuse. Personally, I would like it if every amp in the Axe were MIMICed to the last knob. All these firmware updates, which everyone at FAS has worked tirelessly to give us free of charge, seem to aim for more accuracy with every new update. However, tone is tone. If it sounds good, that's the end of it. Dismiss the tone because of its quality, not its source.
All I am saying is that if we knew which models are MIMICed and which are not, we would know exactly what tonal behavior to expect from each amp and we could apply real life amp settings to them more accurately, which could be crucial for certain live rigs/recordings. This is not to say, of course, that one cannot get a good tone from an amp model which is not MIMICed. May I remind you that a couple of firmwares ago that was all we had. Approximations. And we loved it. As a matter of fact, I still do. In another thread I have mentioned that the Energyball is indispensable for me even though it is not (as I assume) MIMICed. Would my patches sound better if it were a MIMICed Powerball? Maybe. Not necessarily. They could even sound worse for all we know. But that's not the point.
My point is this: I think it would be good to know which of the amps/pedals in the Axe are MIMICed and which aren't. That's all. Which category a certain amp falls under has nothing to do with its tone or popularity, in my opinion at least. Just its accuracy compared to the real thing. Something that is not MIMICed doesn't sound, of itself, bad. It just isn't as accurate. That's not a bad thing.
It is worth knowing though.