What's odd about that? Saavik apparently went from an officer cadet to chief science officer on USS Grissom. And she didn't even save the entire planet from a terrorist attack! More to the point, the fact that Kirk kept screwing up is the main reason he wound up getting demoted. If Pike hadn't vouched for his abilities -- TWICE -- he never would have made it on the Enterprise at all. And STXI went into why Kirk wound up getting command: because Pike himself had hand-picked him to command the ship. STID shows us it's a decision that Pike came to regret as Kirk really WASN'T ready when he took command and on some level even he knew this.