#3: not yet
#5 & #6: Not to pick on Leif, but I am kind of amused how often requests are made to save one keystroke in a user’s specific work process. Not that these things would not be useful, but that it is still early in this program’s development and the roadmap presumably has more important fish to fry (chords, percussion layouts, and repeat endings come to mind based on user requests).
#4, #7, & #8 have been addressed already, either planned (7) or explained (4, 8) in current state.
#9. Actual tempo markings (as opposed to tempo change markings) can be created via the SHIFT-T popover and existing marks can be edited via the Properties panel.