Here are my thoughts on what we know about the second half of S4.
It's nice to know that we will get to see Pre Visla in another fight even though it is only Ahsoka. I'm hoping that his female Lieutenant will have some sort of saber similar to Pre's not just a gun. I'm not too bothered about the return of the separatist senate although I would prefer to see the CIS council, hopefully Passel or Shu Mai will get a mention considering that we will be getting a senator from the Corporate Alliance and a Gossam senator who will most likely be representing the Commerce Guild.
I'm really excited for the bounty hunter/prison break arc because of all the cool bounty hunters that will end up meeting each other. However I am still annoyed that we have to have the main trio for this arc, I was hoping it was going to be from the bounty hunters POV with unknown Jedi. On the bright side we are getting Mace Windu vs Embo, I am looking forward to that.
If Crisis on Naboo is part of the jail break arc, than maybe Massacre will be a stand alone episode showing the fight with Grievous and Ventress. Still not sure what to think of the episode Bounty, will it feature Dengar or will he be in the jail break arc?
As for the Maul and Savage episodes, I am not sure what to make of them yet, but it will be pretty interesting to see how they play out.