Not a bad idea overall. But I do have a few problem worries.
The problem I have is the stacking offence. He gains Offence from his lead, and both his uniques. That is 3 times his offence increases. That is pure overkill. IT's stacking the same thing on top of the same thing for pure power. One of the unique's offence boosts has to go in my opinion.
My worries come from the DoT and the Evasion. Specifically with Darth Maul and Darth Vader lead. Under Darth Maul lead, Sidious will have 55% evasion, which is ridiculous. Like seriously that is high evasion. And Vader lead is pretty obvious. The amount of DoT he places from his unique (especially since Health Steal exist) is a lot. So under a vader lead those will pretty much kill everybody (not even considering the bonus offence from his unique). But what bothers me the most about all of this is that he works best under another person's lead. Like seriously, this is Darth Sidious. The person that manipulated everybody. That played chess against himself with 2 armies. That has always been in full control of almost any situation. And he works best under another lead. It bothers me in the game and it bothers me in your version. Please ad an actual good lead (with a zeta, if necesairy) to him.
But it's overall a pretty good Rework idea. I quite like it. Just worried by the level of power and annoyed hat is leadership still isn't that good. I did a rework idea of Darth Sidious myself quite a while age. Went a completely different direction with it. You can check it out here, if you're interested:
https://forums.galaxy-of-heroes.starwars.ea.com/discussion/204282/darth-sidious-rework-idea