This is an interesting idea, but not a high priority.  One can selectively replace now with [Find], [Replace], and [Replace+Find] buttons. I have been thinking about improving the Search and Replace dialogs, so I will not immediately reject this.  Some additional comments follow.

A changed method name has to be replaced in all use sites, not just in the class definition.  Some editors will make replacements across multiple files.

Renaming a local variable in a def statement, or the loop variable in a for statement (using the [X] whole word option) would be good uses.

[Replace All] could be defined to only apply to a selection when there is a selection.

The new feature would be more useful if there were a 'select suite' or 'select statement' command that would, for instance, select an entire def statement if the cursor were on the first line, with the 'def' keyword.

Currently, on Windows, the 'found' highlight does not work when there is a selection.  That might be a simple fix.  There is already an issue for fixing Search dialogs.

Do you know of any other editors with this feature?