Being an Avenger should mean more....

[Electricmastro]

I think this is a good point. It can boast individual popularity.

Also a rotating roster keeps things interesting I guess.

Yep, as much as some people want to argue the integrity, meaning, worth, etc. of the Avengers, when all is said and done, this is still a series that’s put out there principally to make money off of it as much as possible, as that’s how the business goes, which can include adding more characters to the roster over time which may help boost the sales of said characters in their own solo books.