Smart rests
In a score, let's say the time signature is 3/4, and the bar has a quarter note on the third beat. A way to select a quarter note, drag it into position on the third beat, and then the previous half or quarter rests are automatically added by Musescore. This would save a ton of time, especially in bars that begin with rests, have a few notes, but mostly rests in between. Plus, this feature will make you a sandwich.
Comments
The trick with this is defining a system that can detect what beat you are trying to drag to. Especially if it's not really beat 3 you want, but the "and" of 3. Or the "a" of 2. Anyhow, the idea comes up from time to time, and it's not completely without merit, but I have trouble seeing what's so hard about just entering those rests left to right like you enter everything else. Having to change ones thinking to a totally different way of doing things just for this particular case seems likely to be far slower than just staying within normal left to right entry. Might be interesting to watch the process in a simulation though.