I completely agree, she seemed out of style and balance. But perhaps SG:1 was the more experimental team, they already had Teal'c who could just walk out any time when Jaffa business called and then walk back in. It's not like Carter could do that. And I very much grew to love the character who I was quite eye rolled about in the beginning. I think she had some great interchanges with the others though I did notice that Carter took more of a back seat at that point.. whether this was because Vala was there or for other reasons I don't know.