Fixing 'n' to do what it always should have with map/grep/sort would be a very welcome change. As already pointed out, there is no loss of functionality. Instead of 'n' and 's' both stepping into the map/grep/sort (which is almost never what I want to do), 's' does the old behavior and 'n' does something much better.
Of course, I sent in a near-trivial patch to fix "o warn=0" and got quite bizarre responses from p5p and I've come to expect bizarre responses from p5p so if your prediction is correct it wouldn't be anything "new" from my perspective. But I still think it would be a senseless form of backward compatibility.
Perhaps I should point out that my patch for "o warn=0" restores backward compatability with "O warn=0" from before the whole debugger interface was jumbled around for some reason. It might motivate somebody to apply my two-line patch due to the occasional extreme devotion to backward compatability. But I doubt it.