Hi Peter, i had some ideas to improve getting around ST3 while using the ipad interface on stage see what you think.
At the moment its restrictive and could be made to do things better.

When you are playing a song in a playlist and decide you want to continue with another playlist at the moment you can choose the next playlist select the next song then you have to go back selecting the old playlist to get back to the now playing playlist, i suggest a faster method bouncing back and fourth from now playing song to next song, this is by single tap on a now playing song gets you to next song selection no matter which playlist it is selected in, and by single tap on an already selected next song gets you back to now playing song . This allows us to quickly find and get to the now and next songs selections.
At the moment if you are in a now playing song list and the next song plays that was in another playlist the playlist view does not change to the next songs playlist , it remains on the last played song playlist, this logic does not make sense as you have moved on to a next playlist so the change should also automatically follow so you can keep going selecting next songs in that newly jumped to playlist, at the moment you have to manually find that playlist so you can continue performing within that playlist

I would also go one step further in design where you can go and choose a song in a different playlist and if you double tap on your new next song the waveform of that next song gets shown on screen so you can choose which audio segment you want to start from, once its selected a single tap on next song again brings back the now playing song waveform and another single tap on the next song goes back to the now playing song and the playlist that the song is in.
This creates a fast automated movement between playlists and now and next songs, plus it allows you to go from now playing song end to a next song choice of audio segment .
If you then choose to use Xfade the logic is the now playing loop will neatly Xfade at the end of this loop to the next beginning of the next loop and the playlists will change accordingly to keep going .
So now all you do is enter a new playlist select a next song double tap to choose a loop within that song if required if not then just single tap the next song again to preserve this selection but get back to the now playing playlist and song.
This logic gives us very quick movement to next songs no matter what playlist they are in and also the ability to actually choose within that song a loop to jump to , then simply return to now playing song ,
This requires no new buttons or changes to the interface it purely gives us the ability to move around and create our next requirements with ease.
There should be only one way to stop/start the performance and thats using the stop/start button or foot switch and by using the XFade button which actually does not stop the performance but moves on to the next song.
By introducing easy movement to choose your next thing required would really make life on stage easier.
At the moment it is not as smooth as it could be.
Bouncing around the song using loops is great now , apart from accidentally bringing down the window when choosing loops this is still a major problem if using fingers on screen , i still believe reducing the hit area of the drop down area would help this problem in ST3.
Cheers Damir