Originally posted by Emperordmb
Plagueis probably could've if he hadn't been killed.
Plagueis had over 100 years on Sidious, and Sidious was already his peer by the time of Plagueis's death, so I highly doubt it.
As for the thread, it's possible, but I think it would be inappropriate, as Sidious is the ultimate villain of SW, and his connection to the dark side was deeper than any sith before or after him. It's almost as if he achieved a complete oneness with the dark side (as was suggested in Plagueis), which is why he was naturally more powerful than sith lords like Vitiate or Plagueis, despite not living nearly as long as either of them. He surpassed them in power due to his sheer potency in the dark side, his unique connection to it, and command of it. Although the ROTS novel is filled with hyperbole, it was made clear that Sidious was the darkest center of the dark sider, draining light throughout the galaxy, which is why his very death diffused the dark side, restoring balance to the force. Basically the force itself viewed Sidious as the greater threat than any sith before or after him, which is why Anakin's creation and destiny was to kill him.
This, along with his feats, is why I place Sidious far beyond even Vitiate: his natural potency and unity/unique connection with the dark side. It's not that I'm unwilling to accept Palpatine as having superiors, which I do such as The Son and Abeloth (although I think it's stupid, but I accept it nonetheless). It's not that I'm underestimating Vitiate's power with the force, I just don't see anything to suggest that he approaches Sidious's sheer natural potency with the dark side.
With the new canon, if they do create a superior villain, I would have no choice but to accept it, but, IMO, it would be just as stupid as creating another chosen one.
I know The Son is a character in the new canon, but I think it was the EU that confirmed the Mortis Family's existence, as the Mortis trilogy really didn't confirm them as being actual beings from what I recall; they seemed to be more like realistic illusions created by the force, as even the son implied to a captured Ahsoka that everything that was taking place on the planet was all in her mind. IIRC, the spirit of Qui Gon implied the same thing to Anakin before going to confront the son in an area that was the most potent with the dark side on the planet (which was similar to what Yoda told Luke before entering the cave). To me, it seemed like the force was trying to warn Anakin the dangers of using the dark side, which is why The father, towards the end of the series, admitted that trying to use and tame the dark side within his son was a mistake, because in doing so, his son was slowly consumed by it, which is what eventually happened to Anakin: the more he embraced the dark side, the more he was consumed by it, which is why he eventually became a slave to it (Darth Sidious).