[wizofaus]

If I had to pick one it'd probably be proper support for score instructions that appear over multiple staves. I was involved in trying to design the feature and was supposed to help implement it but a change of circumstances at the time meant I didn't have time to dedicate to it, so a very-much-simplified version was developed separately. I gather basically it requires editing the template files to customise. I do remember there was significant debate over what such a feature should be called, and that the proposed name didn't really make sense to me (I think it was "system text" or something similar).