Apparently, the outcome at Mustafar wasn't expected by Palpatine. He seemed to have expected Anakin to come home intact, in one piece and not needing a full body suit to keep himself alive - the future Lord Vader that Palpatine envisioned the galaxy to see in the coming decades was supposed to look like the man who marched into the Jedi Temple to execute Order 66.
If Vader had returned from Mustafar of good health (missing nothing more than the hand he already lost in Geonosis), and thus easily recognised by all who set their eyes on him to be Anakin Skywalker, does that mean he wouldn't have been covered up as having died defending the Temple?