+1 For a “Freeze All” function.
Me any my friend regularly exchange project files to work on them. However he has different softsynths and VSTi than I have so a “freze all” would be huge time-saver" because frozen tracks are played correctly even if the original synth is not there anymore.
It would also be a great feature to archive our tracks. You never know if you still have all VSTis when you open up that track half a year later…