Question: What is the point of including a weakness like the crotch vulnerable spot on your robot? Ivan opened himself up for that one.
Question: Where are Baboo, Squat and Finster?
Answer: They weren't even considered to appear in the movie considering there were so many other changes (different suits, new Command Centre etc). Also the movie has been widely accepted as out of continuity with the TV show, so their disappearance doesn't really mean much.
Answer: There's never a "point" to including a weakspot, by definition they are a flaw in the design that is either unforeseen or unavoidable. Maybe they could not find a way round it when building the robot, or any solutions simply created other weakspots.