Woman in CG are stupid? Are you watching the show?
C.C. - err let's skip she is pretty clever when not in deredere mode.
Nina - Genius
Ceciel - she is pretty cleaver too.
Euphamia - she definitely know her ways of getting what she want... not clever, but not dumb.
Cornalia - she can even battle Luluche in chess.
Viletta - Definitely not stupid, she is not guided by cocks anymore once she have her memory back.
The president - the planner type. Wicked clever.
Nannaly - "She knows more than she appear": FO
Luluche's mom - VERY clever, she probably plan this stupid story out in details.