If they had to make the change should have matched the Jedi makeup, used the original line reading and had Ian McDiarmid use the same inflection. Just so you know this is a 2004 change the original Emperor is in the 1997 version of the Special Edition. Just like Jason Wingreen is also Boba Fett not Temuera Morrison in the 97 edit of Empire.
IIRC they just pulled Ian aside one day on-set for RotS. That’s why the makeup doesn’t match.
What’s really depressing with the later releases of the OT is how little effort they put in after the 2000s.