Professional Printing PDF Export Options
Although PDF files exported by MuseScore are perfect for printing, and give high-quality results, large printing houses require PDF/X-1 or PDF/X-3 formats.
CURRENT BEHAVIOUR: MuseScore exports to standard PDF-1.4 format.
CURRENT WORKAROUND: Expensive external PDF manipulation software like Adobe Acrobat.
DESIRED BEHAVIOUR: Options to export to PDF/X formats, including using CMYK colour-space and possibly ICC profiles. (The excellent people at the Scribus project might be able to help)
NEED FOR FEATURE: 8/10
(This is one of 8 features I am suggesting concerning printing/layout in MuseScore, with publishing houses' standards in mind. The score out of 10 is how badly I feel this feature is lacking.)