I'm glad this thread got bumped. I've been meaning to post a follow-up comment.
HippieTim was right - high-gain tube amps react the same way as the Axe FX with regard to volume knob response.
Personally I like tubes in the water and tubes on land. A wave pool is just not the same...
I love my THD Flexi 50 for the way it responds to the guitar's volume knob and touch. Sadly, it rearranges the furniture when I'm running it in its sweet spot.
A couple of months ago, I captured its speaker cab in an IR and tone matched the Flexi in my Axe-II.
Last weekend I was noodling around on what I thought was the Plexi Treble patch in the Axe-II, thinking "gawd this is a great sound!" Looked over, and it was my homebrew Flexi patch
You owe it to yourself to try the Jumpered Plexi patch that's in the new-ish version 11 firmware. Pure awesomeness in grit, spank, punch, and the way it cleans up when you roll the volume knob back.
Yeah, I'm an Axe-Fx II guy.