Well Morgan, the trade-off between simplicity and functionality in sound decoders is that the better sound decoders are complex in order to maximize the sound fidelity. Think of the QSI, ESU, and ZIMO sound decoders being like some esoteric HiFi home sound systems which have zillions of knobs, dials and sliders for the audiophile owner to mess around with. There aren't many of those audiophiles around. Most average humans are happy with a simple Stereo HiFi system in their house, with just volume, balance and tone controls.
I suppose you can struggle through using a QSI (or ESU or ZIMO) decoders by asking others to help you, but if you aren't willing (or not able) to at least somewhat immerse yourself in the manuals to better understand how those complex decoders operate, maybe a better choice for you would be to use some more basic sound decoders. Digitrax, and MRC offer such simpler decoders. Then there are middle-of-the-road decoders like Soundtraxx Tsunami and TCS, which offer better quality sound than basic decoders, but that again also means that they are more complicated to set up (more CVs to mess with).
I don't really think QSI decoders are any "quirkier" than ESU or ZIMO. They simply are very feature-rich (read: complex) sound decoders, These three companies also provide dedicated software/hardware to make their decoder configuration more intuitive. None of the simpler decoder manufacturers do that (because it is not really needed).
As far as SPROG goes, (or any DCC system that uses programming track) goes, the problem is that when the DCC specifications were developed, there were no sound decoders to even consider. Sound decoders draw a lot more current (due to them containing all the additional sound generating circuitry), and that affects the operation on the programming track. It is unfortunate but we have to live with that (or just go with simpler decoders).