That's a fine idea. However, a small bit of information to help achieve a nominal input level to the grid has the advantage that it could be included in the preset itself. And it wouldn't require any effort on the part of the author. And it would work even if the preset came from somewhere other than Axechange (for example factory presets). I believe it would be a big help in solving the problem. But your idea would be a great addition to Axechange.
yes, and thinking about it in the preset sharing use case, even with a DI and output sample from the sharer, the challenge is often that the sharee does not have the same guitar to work with, so having an automated input gain level calibration with the shared DI as target but using the sharee's guitar would help with tone replication in this context - still a lot of variables as stated above (ie the sharer's hands / hard picker / soft picker ...) but I'm starting to see how this could be helpful.
It could be in addition to; so optional. There lot's of features in Axefx that are in addition to authentic application but which do not diminish it - ie being able to raise gain at input/before the amp without a pedal and tonnes of other stuff. I agree though, in that the ability to have my guitar through Axefx sound exactly like my guitar through a real amp should not (would likely not ever from what I know of Fractal) be compromised.
Another advantage it would solve is the issue I mentioned above, when you're forced to use a different guitar in the middle of show for whatever reason. Especially when you're using 24 presets and going back and forth between presets you set up for guitar 1 and others you set up for guitar 2. Having the input gain set automatically would be a big timesaver as the show runs from one song to another with very little break in between.
This isn't about output levels between presets at all... It's about feeding a more consistent input level to the same preset when using different guitars.