Hahah. This is actually a really good point. Before Brian Bendis did what he did with that storyline, did Scarlet Witch ever do anything remotely comparable to that? Because what she did there essentially was become a walking talking reality stone/cosmic cube on a global [galactic?] scale. Which is cool and all.. but if that was just something Bendis pulled out of his ass [before removing her for like 5-6 years right after]... then that's "Spider-Man vs Firelord" territory as the nerds used to say.
She did help drive back the Phoenix later, but bendis' damage was done