Number ONE would have to be having separate HPF & LPF for Main outs and Monitor outs. I know there is separate EQ for both, but my monitor cab with powerhead is very woofy at low volume and just fine direct into the board, and Taking the bass from the monitor EQ isn't the best fix. If Main and monitor outs each had their own HPF & LPF you could better match eq between direct to house/board and your monitor cab sound, and I hopefully wouldn't be too hard to implement.
#2 being the offset able tuner thing where you hit your E string tuned to Eb and it reads E........