If I could have split my vote, I'd have given it 3 ZPMs for the concept, but they were relying on Rachel to pull it off, so it gets a below average for lack of credibility.
Teyla couldn't have convinced her kid -- much less another queen -- that she was a WQ. So it loses points for plot device: The Primary (who must have been one of the slower kids in school) believes Teyla is a WQ because the script says so.
ETA: Having now read the comments, I'm astonished. Go back and re-watch the episodes that had wraith queens in them. Teyla displays none of the contempt or bearing of her "predecessors."
Yes, Teyla is really gentle and kind, but her life -- and Todd's, who I agree was great as usual -- depended on her being convincing (and just being bossy didn't cut it).
What could have made this a little more fun -- seeing as they cut the opening credits (to save time for the episode?) -- would have been a "My Fair Lady" scene where Todd coaches her on the "proper demeanor" of a WQ.