They finally really did it
You maniacs! You blew it up! Aw damn you! God damn you all to hell!
I don't mind having Vader appear and even being active in the show. What I'm disappointed with is him meeting Obi-Wan face-to-face and engaging in battle. Disney just blew a Sea of Tranquillity-sized plot hole into the Star Wars canon. And it was totally unnecessary.