> One thing I remember though, was that the multi-cursor+selection approach only really helps when you can see everything you're about to change on the screen. For large edits, most selections will be out of the scroll window and not really helping.

In Emacs, there's an mc-hide-unmatched-lines command that temporarily hides the lines between the ones with cursors. This makes multiple cursors usable with up to a screen-height number of items (being able to place cursors by searching for a regexp helps).

I agree, though - MCs are most useful for simple, localized edits. They're nice because they don't require you to mentally switch between interactive and batch editing modes, while still giving you some of the batch mode benefits. For larger or more complex edits, a batch-mode tool ("Search and replace", editable occur-mode in Emacs, or even shelling out to sed) is often a better choice.