It sounds like this season is going to show Anakins fall (or the set up for it), what lead to the schism between Palpatine and Dooku, and the revenge of Darth Maul.
The big question is will Asajj Ventress survive the season or the series?
I don't think Asajj, Savage, nor Maul will survive. The trailer shows Palpatine going on a hunt to enforce the sith code of one master and one student. This could be a fascinating storyline for the season plus a neat added dimension to the scene in episode three when Palpatine has Anakin murder Duku. A final lesson on how proper sith transfer one student to another.
Thanks for your feedback! Team Branch