I think it's subtle, adds to his character when it comes to his feelings towards the Jedi, Qui-Gon and the Republic as he explains to Obi-Wan in Attack of the Clones, and it doesn't contradict anything.

Welcome!

Not a bad idea but Maybe a bit confusing placing it right after the "master or apprentice?" line. The audience would know that he's not Sidious unmasked (the beard!) but it would lead to think that there's a link. (and could be really confusing if Sidious face is completely hidden through all the movie.) But after all, there is the pan on Palapatine face... that should be enough hint to the audience to not make confusion.

Also adding a new character at the very end of the movie is a bit odd. But why not, and I agree it would add more depth to the character. It would be a nice scene on its own; it's just the moment it is integrate that bugs me a little.

Sorry for my english.

French guy here.