"Even though Kennedy is injured, do they really need to strip him of his MITB shot?"
No, if Taker wasn't hurt, this most likely wouldn't have happened. But now they need to fill 2 main event spot on SD!, and only have Mark Henry to fill the "upper mid-card role" that Kennedy had. Edge takes Taker's spot as Batista's main foil.
It sucks, hurts Kennedy's credibility big time, slightly hurts the MITB concept, but will lead to a fun SD! main event.
They probably had Kennedy look like shit tonight because this is twice he's gotten injured after they decided to "God Push" him.