Musescore 3: full backward-compatibility, please
I've been meaning to post about this for some time and just never got around to it. Anyway, my biggest peeve about Musescore 2, improved as it is, is the REALLY annoying problem of initial backward-incompatibility with files created in Musescore 1, which forces you to save your old files all over again in Musescore 2 before you can make any changes with them. Essentially, it turns them into read-only files until you re-save them.
I know it seems like a simple operation, but it irritates me sufficiently that it acts as a significant deterrent when I contemplate using older Musescore files posted in the Sheet Music section. There's a lot of great public domain/CCzero stuff here. Unfortunately, that that initial-save issue, along with the frequent "corruption" that ensues with the older files (when Musescore says that it found X number of beats when it expected Y), holds me back from taking advantage of a good deal of the available material that I might otherwise download and use.
So if at all possible, please avoid this issue in Musescore 3. I have boatloads of Musescore 2 files, and if I have to reopen and resave every single one of them at the transition, you will probably lose this user.
Another item on my wishlist, though secondary, is that you get rid of the hidden files automatically generated when saving. I exercise complete control over my system, so of course I have it set to show hidden files, and these things are a significant annoyance; I spend a lot of time deleting them so they don't cause confusion. If it's not too much trouble, please get rid of them. Or at least let us turn them off.