Just adding my three pennies-worth to this thread -

I also would like to create stage plots in the web interface. To me, it makes more sense to do this on a bigger screen with a proper keyboard for typing. If the plots sync to the apps, then the apps can be used for printing PDF - although, the set lists can be printed as PDFs from the web interface, so it seems the problem of creating them there is solved?
Reason why I prefer the web interface? Frankly, clicking on the + signs and tapping to add things on my Android devices seems to be hit and miss. Sometimes nothing happens, sometimes it does if i wait several seconds without touching, sometimes not. Sometimes it happens instantly. At least with a mouse click or keypress I know for certain the input is registered by the device. Input recognition is better on iPad but still offer potential frustration.
So, Stage Plots in the web interface is loads of work to implement, no doubt - but would be a winner for me. I've kind of given up trying on my Android devices, as a luxury that a bit too tricky to bother with.

RG