I think in general editors should be unsurprising. If there's a general expectation of "if text is selected, and you do a WRITE_TEXT action, then the selected

I think in general editors should be unsurprising. If there's a general expectation of "if text is selected, and you do a WRITE_TEXT action, then the selected text is replaced with text"; and if CTRL_V is a WRITE_TEXT action; then doing CTRL_V after selecting text should replace the selected text. Then again, the above rule already has exceptions; eg writing a parenthesis in some editors will surround the text with parentheses.