They've been working toward this forever. They're the same concise pop songs as So Jealous, just with different production (seriously do it with a DI acoustic guitar and it could have come right off that album). And they started to embrace little 80's/dance-y touches on Sainthood. It's a perfectly logical progression for them to try.
i agree with the 80's dance direction but i think it was done in a more original way. It doesn't bother me when a collaboration with a dance/electronic artist like tiesto or morgan page sounds like a dance song with a different style of lyrics but this song is a tegan and sara song. Its been 3 years since they released an album and i guess i was expecting something a little more. The whole "let's make things physical" really erks me. Leave that to the lady gagas and the carly rae jepsons...I dont disagree with artist going in different directions but at least make it SOUND like it could be a song from you (being the artist) either lyrically or by some stylistic choices that are staples of the band/artist. Anyway i didn't mean to diss their "artistic integrity" cause if this is a song they truly care about then more power to them.