I think you're being unnecessarily harsh considering that it's not a paid option. That being said the lack of a graceful reflow option that allows you to delete/add/insert notes and have everything reflow across the musical bars drives me absolutely nuts, and is one of the foundational reasons why I don't use MuseScore.

As a result, I end up having to do a great deal of musical arrangement work in guitar pro of all applications. Then I can export and import it into MuseScore for final touches.