Palpatine ruled something like 23 years as Emperor of Galactic Empire. He has claimed he wants to ["harness the full powers of the dark side"][1]. But did he actually learn anything useful that he didn't know as a Chancellor ? 

I'm mostly interested in Canon, I know that in Legends he could be [reborn][2] and create [Force storms][3]. But in Canon, his powers are mostly stagnant except little adventure with [Lothal Temple][4] and time travel. Am I missing something ? 


  [1]: https://scifi.stackexchange.com/questions/141878/did-the-emperor-intend-to-live-forever-if-so-how
  [2]: http://starwars.wikia.com/wiki/Palpatine
  [3]: http://starwars.wikia.com/wiki/Force_storm_(wormhole)
  [4]: http://starwars.wikia.com/wiki/Lothal_Jedi_Temple