I think that's a pretty good question. The only ones that may be able to answer would be Cliff or maybe one of the beta tester guys.
As for the "same settings as a real amp" nah, I don't think anyone really expects that nor would they hold it against Cliff for not being exact. I personally think some of our amps sound better than the originals....and I mean that sincerely. Others seem to sound weird to me...but again, there are several things that need to be factored in. I only use about 4 different cab models. So some amps are going to suffer for me...and rightfully so if the cab is not the right fit. You have to try anything and everything really. At the end of the day, I'm happy to have my Axe over the Kemper. I've had a few K's in my studio....and though they were definitely cool....I'm happy with what I have.
Unfortunately, it's not that easy rik. So many things change sometimes, you don't know where to start....new options added....the list goes on and on. For example, I've not updated my XL+ since 18.4. That FW just worked for me and gave me what I needed. If I would have done what you said and recorded a song into my pc, and then even took screen shots of every menu (which I have done many times lol) in my AxeFx amp block, I would STILL fail trying to get my old sound with the new FW nor would I know what actually changed or why.
When you add things, change things, re-calibrate things....you get a brand new unit on some of these updates. In my case, I got 3 updates worth of brand new units in one and everything from my effects to my amp blocks and even cab options have changed. Even though I've mentioned a few things there....if you were to get Cliff to explain it, those little things I just mentioned probably turn into 600 changes per option internally.
Funny story real fast....when I was developing VST plugins for a company, we came up with this one build that was absolute sickness....in a good way. To me it was one of the best VST plugs we ever did out of the 1000 different builds lol. Anyway....this one took 11 seconds before it loaded up into your DAW. That's definitely a bummer and not good at all. If you had two instances of the plug, that was 22 seconds before you'd see them. 3 instances....add another 11 seconds and so on. That said, the sound was incredible but we were trying something different to get it to sound like that and the downside was the load time for where we were at THAT time in the software world.
That "different" had all the right stuff. We just had to find a way to make it load faster...which we did in fact figure out. But my reason for saying this....I happened to ask the owner why this happens and he said "picture an amp builder literally creating the plug from scratch when you initiate an instance....there are 400+ things happening as that plug loads."
Unacceptable to the buying public if you were to tell them that....they just want the thing to load fast and work right. LOL! But in that same situation, we probably have a lot of that going on with our Axe FX....but we have all the right stuff to do those 400+ changes in an instant. Add in new FW with a bunch of new options and changes and man....I can't even fathom how many things may be going on. So you never really know what has changed or how it has changed your particular sound. Like I say though, maybe Cliff can sum it up in a few sentences or so....but I'm not so sure.
I can say how it changed my situation. It changed everything for me....in a good way. More warmth and tube sound...less transistor/synthetic bite, tone stack seems to fit the amps better, pinch harmonics sound more like the pinch harms you get out of a tube amp instead of how they sound when you do them using a transistor sound. This is super important to me because I absolutely hate the sound of synthetic pinch harms. Think Eddie Van Halen....when he pinch harms, they scream in a way that hit you in the throat.
The sustain is really there now. We always had loads of drive in the axe, but I've always felt that in certain situations, the notes would die out where this never happened using my tube pre-amps or my regular amps. I've tried everything in the Axe and just chalked it up as one of those things I would have to try and compensate for....which I have. With this FW, I'm not getting that "die out" like I used to and am not using as much gain. I used to compensate using a little more gain or I jacked up my compressor output to push things a little more on my lead sound. All that is different and for the better now.
There's a certain (and this one I really can't even explain right to you) feel or the way an amp reacts. We are getting that same reaction now. We've always been close in my opinion, but this is so close to me, I don't think about it anymore. What all this means technically compared to my old sounds? I really don't care lol....I'm just happy it is the way it is. I'm not even going to question it.....in the time it has taken me to even give you my personal guess and experience, I could have had another one of my tones tweaked for Quantum. Hahahahaha! None of the AxeFx firmware builds were bad. The thing sounded great when I got it 2-3 years ago. But this one definitely is a game changer for the better.
Just be happy you were born into it....you can create for the first time and be blown away. Enjoy!
-Danny