Manual sample rate option
Being able to manually set the MuseScore sample rate/bit depth would save me from having to change my system-wide sample rate every time I use MuseScore.
Also, a weird bug I noticed on my system while using MuseScore at really high sample rates for testing (ex. 32 bit 384 kHz) is that the performance gets anywhere between 2x-3x better if the score is actively being dragged around during playback.