Do you think a character like Wanda can ever have an existence separate from the Avengers? The end of her series was kind of sad (maybe semi-intentionally) because she tried to find a life for herself separate from the Avengers and then asked them to take her back, which happens every time she tries to find her own way. Same thing happened to Vision - Avengers Assemble Annual ended with him saying he needed to find his own place, and he never did. Are they just stuck with their team like X-Men?
I don’t think she can ever be entirely separate from the Avengers in the comics (adaptations are another matter), but that’s okay. I talk a lot about Wanda’s fluidity as a character, but her true status quo in 616 is as an Avenger. That is the place to which she always returns, and it’s good for characters to have that place.
However, I think the situation with her and Vizh is different from the X-Men. They return to the Avengers solely because that is their home book, their natural place in the MU, thanks to decades of storytelling. It’s where they fit because they are entwined with the Avengers mythos.
That’s true of the X-Men too, but with X-characters, there is an additional layer. They are pulled to that central hub of The Team because the mutant metaphor is at the heart of both the team and all the characters on it. There are loads of X-Men who are compelling on their own, but they are all elevated by the power of that metaphor. The idea of the X-Men is stronger than any of the individual characters.
The thematic strength of the X-Men is leagues above any other superhero team. They are united in a way that teams composed of disparate people just deciding to be heroes aren’t, and when the metaphor is done well, the characters tend to work better. Rising tide lifts all boats.