I’ve never liked it when prequel edits try to make Palpatine being Sidious less obvious. I feel like that’s actually something that makes the prequel trilogy really work. It’s the whole Hitchcock “tension is better then surprise” kinda thing. It’s more thrilling to see the villain being there working behind the scenes the whole time and the characters not suspecting anything. It allows the audience to admire Palpatine for his planning, manipulation and two-faced nature. I’d rather have more character development for Palpatine then a surprise.
There’s not really any way Lucas could’ve done it without it being obvious anyway. It’s the same actor. He’s the old guy who becomes Chancellor. Of course it’s the Emperor. Lucas isn’t JJ Abrams, he doesn’t try to make everything into a cheap surprise. So he chose to ring out the tension and show Ian McDiarmid’s strength as an actor.
The prequels are really built around the idea that the audience is familiar with the fates of its characters already, so it does feel a bit silly to mask them for surprise value.