Maybe I misunderstood but there is plenty of talk about reducing the complexity and thus you have to be careful about dumbing down the other richness of features. I was pointing out you need to be careful about reducing the existing functionality. I have seen that happen far too many times before in the quest for progress and was think it is a fair warning to point this out.
For the 2 panels I think that is the way that most others do it and I personally I cannot think of an easier way of doing it.
There is “before” state and an “after” state. Obviously (as has been stated before (not just here on this thread but many years in the past)) we need text descriptions on it e.g.“Current/original files” for the left and “New/proposed files” for the after.
But the concept of the 2 panels was questioned and I think is fairly self explanatory. If you have a better suggestion please share.