This function is pretty common in the DAW/sequencer world, but I find it useful for score editing as well. Basically, it's just a step forward from the basic Insert After functionality, but it would further eliminate the unnecessary select-copy-paste operations across multiple staves.
1) Select several consecutive measures (or just one, but it would be more commonly used for groups of 2, 4, etc.). It should be enough to select measures on any staff, and it would work for all staves.
2) Click "Duplicate selected" or hit the corresponding keyboard shortcut.
3) The exact copy of the selected measures is inserted after the selected occurance.
4) You can then edit what's different while having what stays the same (like the rhythm section).
Another variant may be selecting measures across several staves, and their content would be duplicated, while on the rest of the staves the inserted measures would be blank. In different situations either of the options may prove more convenient. Probably the best would be to have both variants of the command available.