Mortis arc SUCKED. It wasn't the worst of The Clone Wars, but that only says something about how generally awful TCW could sink. To see it referenced... hurt me.
It took the metaphysical ideals of the Force and made them physical as actual, boring, and killable gods; it took the prophecy of the Chosen One (with its twist of 'bringing balance to the Force' meaning he kills both sides) and urinates all over the only halfway clever idea to come out of the prequels; and what's more it ends with a "It was all a dream... OR WAS IT!?" straight from the worst movies of the 1950s.
I was totally unsurprised to hear Pablo Hidalgo mention in Rebels Recon that it was Lucas's idea to put the Mortis arc into The Clone Wars, it had his prints all over it.
I won't lie, I actually rolled my eyes and said, "WHAT?!" when I saw that wall painting. After all the work the crew has done to lay out a subtle, nuanced notion of the Force, to see one of the most boneheaded TCW episodes reference...
But other than that, it was a good episode, and I am looking forward to the next one. Always nice to see Palpatine, he's just enjoying himself so much. I can't say that I liked Ahsoka living, but I don't have a hate for the idea either. Some great quips, and that moment when you saw Kanan's ghost touching Hera's shoulder...