Re: Should they introduce Kara Zor-El in the sequels?
What does Jason have to do with Kara Zor-El?
The comics had Kon-El (the half breed Kryptonian) and Supergirl fighting side by side as part of the Superman family for some time prior to his death.
Theres room for 3, or 2 and 1/2,.... but I'd say its way too soon now for Supergirl now.
Maybe someday around the time Nolan concedes to bring Robin in.