Mon pt de vue :
Mk2 user here, and in love with it.
Never use old FW !!!
Never because the soul of the AFX is to move forward to better modeling. Period.
So get rid of these and keep us updated, please cliff, as far as you can in terms of IT Techs.
What's more i'm fully ok to get rid of some advanced param i never use. And even less amp choice... there are so many amp in fact as a vast majority of peop' I use about 10 amps max. ok... and i move from 10 to others tens ...!!
What makes sense for me is to have the last fw for better feeling and sound texture, staying as simple as possible on the amp usage. With a good modeling amp, my point of view is that standard params along with eq are widely enought to get to great tone.