The only use for Palpatine having access to a saber, narratively speaking would be to convince Anakin that the frail democratically elected leader of the Republic is trying to defend himself with very little effect against Mace Windu. In that instance it should be not his but picked up from a previous killed Jedi and should be disguarded once Anakin has killed the Jedi Master defending the Chancellor. I wouldn’t actually had Yoda in the prequels at all but have had him mentioned with awe and reverence by the Temple Jedi. That way Luke’s surprise and first time viewers surprise is maintained. I would have drawn a line between Jedi and Jedi Knights. Ben is retired military, Yoda is a religious hermit.