I don't see the need for any physical interfaces other than the foot switches, led's and color LCD.
Any tweaking of anything can be much better handled in the app.
I agree that spill-over and tone are great strengths of the player. I also agree that a certain type of musician will find these features alone outweigh any other weaknesses.
My concern is that there are more people that will choose the sexier device.
Of course, this is just my thoughts.
I already have a rack and fc. If I were to by anything else it would be the new player. This is because I would want to reuse my sounds and rigs.
If I were in the market for a small device in the $500-$700 range and didn't already have a KPA, I would be likely to buy a device with a color LCD.
My guess is that there are many more potential customers that would say the same vs. those that either have a KPA or would choose to believe that the Player's tone difference was a good trade off for the color LCD.
Again, I could be wrong.