MarkGuitar Just trying to better understand what you are asking.
Hi Mark , if you go to ST3 you will notice in bottom right of lyrics screen two buttons , one is used for Xfading from now playing song to the Next selected song  , the button just above it with a circle that looks like a loop controls the Audio segment looping status , this button goes bright yellow when you activate a permanent loop on the now playing Audio segment , this is very useful because you can repeat a verse or chorus or activate it on a solo and do a 20 min solo if you like , very useful function , these two buttons are always there and you can always depend on them to do their job , you still have two assignable buttons as well .
On ST4 you need to waste assignable space to enable these functions but that’s not the problem , the issue is these buttons don’t highlight and glow nicely to indicate they are on , the logic of the audio segment looping control is different on the assignable buttons as you can’t just activate on off the permanent loop function , you need to step through 4 push buttons to hopefully end up in a setting you need with no positive indication on the assignable button to which mode of that button you are on , as the indicators on the audio segment buttons a small you can’t identify to which mode you are on at a distance , this all sucks very hard and is unusable while performing , these things are very important and to understand them you need to put yourself on stage and imagine using them, perhaps try ST3 first then try ST4 and see what I mean.
To replace these functions with a zoom is a big slap in the face  especially when there is absolutely nothing wrong with pinch  zoom  especially when it’s adjusted to work nicely and has an indicator to indicate it’s absolutely position , why is zoom so important to you ? Don’t you set up your zoom points at home , all my songs sit on 50 if they have a lot of lyrics I shrink the zoom to 42 and anything in between for other songs , once set I never need zoom again, but I can’t perform well without the other two functions and all my other assignment buttons have SPEED up down, SONG SELECT up down, AUDIO MUTE, SEGMENT SELECT left right .
Some gigs I use foot control smaller gigs I just use the interface  which is important I have all the things I need are at my finger tips .
The removal of the XFADE and simple LOOP activate button id definitely a big ste backward for on stage users.
Peter is working on assignable buttons but no matter what he does there it won’t replace the old buttons where zoom is now , why can’t you assign your zoom buttons in the assignable buttons instead since you only need them to zoom in out they don’t need to light up like the loop button ?