Suggestion split mono cue

Hi it's been more than 3 years since someone suggest the inclusion of mono split cue. It's a really good feature that some of you're concurent have and really i think just for this i am willing pay 300$ beacause this enable many other djing technique. It's not so complicated, i looked at your setting, and you can just add an option to differentiate the master from the master cue and put the master cue in mono and the master in stereo. You allready started doing it with the ddj 200 a 100$ controller so why can you just do the same thing for the flx 4 or the newest controlle. Smart cfx is just gadgets like the smart fader, the less i use it the better i like djing and this option can really make a difference bettween the ddj 400 and the newest controller.