Yeah, for people who are coming in late, the Legends recaps will be really useful (and for casuals who are coming in cold and might want to watch because of hype around a certain show).
I wouldn't really call Wanda a "B" character though. Sure, she isn't Iron Man, Spidey, Hulk, Thor or whatever, but they're the only A+++ Avengers that I'd list. Scarlett Witch at the very least is an A+ level Avenger, but I'd argue even higher as she's the most powerful Avenger not named Captain Marvel.