Does autoplacement move left & right or up and down only?
I wonder if text added above the stave (rehearsal mark, chord, stave text ...) is (only slightly obviously) moved left and right by autoplacement?
I have the impression that it isn't the case, and that sometimes the algorithm could be smarter and very slightly move the text left or right to improve the layout, e.g. to avoid to put repeat lines quite high.
The marketing email that we have just received from MuseScore "3 Reasons why you should use MuseScore 3" is a good example.
The smart layout example of this email is poor: by moving very slightly the text "To coda" to the left, the repeat line could be set a reasonable distance of the stave while in the example it must be set very high just to avoid the end of the letter "a" from "To coda".
Comments
Very good points
The only elements I can think of where autoplace currently moves the element itself left or right is for hairpins, which will move horizontally to avoid a dynamic. There are other places where it change the spacing of the measure as a whole to avoid a collision horizontally - does this for lyrics, chord symbols, falls. And of course, places where it simply spaces for readability - basic note/dot/accidental positioning, ensuring readable ties and glissandi, etc.
Anyhow, while we don't current move things by default to achieve the results you describe, we completely support the user doing this manually - no need to turn off automatic placement, and in fact, it works best if you don't. Nudge things left/right and everything else just falls into place around it.
Figuring out when it makes sense to move things horizontally away from their standard locations and when it does not is, I think, a job left to the human expert, anything we tried to do algorithmically would be something people disagreed with half the time and then complained the results weren't predictable (I'd be among those making that complaint).