Hi Jim
If you rewind for a lower kV that might work great on a 21x14, but anyone that wants to run say a 20x15 is now likely lacking performance, so you get into the area of maybe needing two winds for different props. You are quite right though, as packs improve the winds need to be re-evaluated, and that is certainly a discussion we can have while in Portugal since the Pletty's will be there and there will be opportunity for a lot of feedback. Right now I know they are busy with other projects like the thrust vectoring assembly
An interesting development is going to be coming from Schulze as well, I think they are calling it volt-control and its available on their larger ESC's but are likely going to produce an F3A size controller with the same. Essentially as I understand it you dictate to the ESC what full throttle RPM you wish to have and as long as your battery is of sufficient voltage to deliver that the ESC would automatically calibrate the throttle during flight to ensure you always have the same top end RPM and therefore response. This is will be a lot more reliable and repeatable than setting the ATV. Although not as direct a solution its would provide a bit of compromise.