It will be very useful for contemporary composers to have a couple of tools for drawing (free line, straight lines, circles and squares). in way that will allow to combine in a score "hand written" parts and the standard software writing.
It will also be useful to be able to make a bar blank (without staff) without having to hide the entire staff.
None of the existing software support this to my knowledge.
It'll be great to have that feature on Musescore 4 !
Drawing tools definitely make sense to add someday. meanwhile b aware you can easily paste in an SVG created in Inkspace or whatever.
You can already make a single bar blank, in a number of ways. One is the checkboxes in Measure Properties. Another that is simpler if it's really 'all the empty measures" you want to make invisible - use the Cutaway option in Staff/Part Properties. You can use that alone or in conjunction with "Hide when empty" to make the staff disappear entirely for a system or not.