Scarlet Witch was also extremely powerful, now that I think about it. Outside of the mind raping, she stopped a derailed train, pretty much disintegrated a swarm of Ultron bots, and eventually tore final Ultron's chest open which, from Tony's comments when he sees it the first time, was at least partly vibranium (though he was somewhat damaged already from the earlier onslaught). And she used her powers to shield herself and others from energy beams etc. so she isn't without defences either.
__________________ Never take life seriously. Nobody gets out alive anyway.
We saw hawkeye being able to put Scarlet witch down, and he was even in a position to kill her if her brother hadn't saved her.
Scarlet Witch is a major glass canon, and she really won't be able to do much if Thor goes for an instant kill and throws his hammer at her.
Falcon is of course a non factor, with even Hawkeye having a way to kill him.
Iron mans suit is superior to that of War machines I believe, and even if that's not true, he ain't taking out Stark, Banner, or Thor.
Vision poses the biggest threat here, but he lacks the feats to take on Hulk/Thor/Tony and be able to help his teammates at one time.
He can't pull his team when he has the hulk to worry about, and two of his teammates have standard human durability (mines War machine due to his suit), and both not being power houses, and just one of them have hax.
Scarlet is a major threat no doubt. but she doesn't have the speed to keep up with any of the Avengers when they know she's there.
The only reason she was able to do it the first time was because she had the element of surprise.