Personally I felt the Force Wielders episodes were kind of lame, i thought obviously the stuff with Mandalore was incredibly lame... I liked this last episode arc, and Kamino. Other than those two storylines, Season 3 is definitely the weakest season of the series.
I agree with you on the "Force Trilogy" - everything the main characters learn, they eventually forget - it's like there was no point in that trilogy at all. It may as well have never happened.
Anything Mandalore-related this season was an atrocity. A complete waste - Filoni mentioned somewhere before that this is all supposed to tie in with the show at a later time, but, really now, we all know what happens in ROTS. There was really no need for any of the political crap we put up with. Politics have NO place whatsoever in a show aimed for kids. Period.
Even the Savage trilogy was weak. Lots of overrided canon, and I feel like he was used only as a marketing ploy for this season, when it turns out he's only in 2 episodes. Heck, Filoni should have made the entire 2nd half of the season all about him!
I really can't imagine what Season 4 is going to center around. If anything, make half the season about Savage and Maul striking at the galaxy, and make the second half about Ahsoka turning to the darkside or something.