As much as I love working in Dorico but editing existing music is a real chore. Especially when you discover that something like a 4/4 bar has to be changed into 3/4 in the middle of a piece. It often takes me longer to figure out how to do this than it would rewriting the whole tune. Maybe I am missing some existing editing mode that lets me easily do that. As ‘dumb’ as Finale feels now (sorry), but at least it doesn’t try to reflow everything unless I ask it to.
This is a case for using “Select to End of Flow” and then Alt-L/R to move the music that follows (after you’ve put in the requires meter change).
It’s interesting you say that, because I have found the opposite to be true for me: it’s much easier for me to do this in Dorico than other notation software. Look into switching between insert mode, and moving the notes by grid values (as Dan suggests).
For me, I’d just insert a 4/4 time signature at the beginning of the following measure as a sort of scaffold to keep things tidy. Then I’d put the 3/4 time signature in, and then using the System Track, delete the leftover 1-beat measure.
A more accurate title for the thread would be “Changing music is different from previous notation software”. And I am glad it is.
Try not to use old habits and you’ll learn how much more flexible this is.
With Finale (and Sibelius to a lesser extent) the user interface is so inconsistent you just have to learn a lot of “recipes” for doing different things. With Dorico, if you figure out the logic behind what it is doing, you don’t need to learn the exact procedure to do every particular variation.
Right now I’m in the middle of editing a score by a composer who often wrote time signatures like 23/4 (and a different time signature for every bar of the score!) and splitting up those long bars into something readable. The fact that Dorico does “reflow everything” (and if my first idea for splitting the bar puts a barline right through the middle of some nested tuplets, I can just try a different way without breaking anything) is a pretty good reason NOT to want to use Finale for that job 
Agreed, or changing the title to “Changing music is note easy in Dorico”! 
C’est exactement ce que je pensais aussi.