Re: Team Sif/Team Foster?
Are you talking about the movie or the comics? 'Cause Jane was certainly not particularly smart in the comics. She was a ditzy damsel in distress for most of her existence. It wasn't until she was brought back as a full-on doctor rather than a nurse decades later that she showed a modicum of brainpower.
"This I grant to you: You may tell your grandchildren that you stood for a time against the mighty Thor."
- Marvel Heroes