What always gets me about those movies or just ballet in general in cartoons is the lack of properly using turnout and pointing of the feet. These are things a dancer pays attention to whereas a "normal" person may tend to brush over. Hands as well and the por de bras I feel is also often overlooked. When there is no shape even to the finger tips it bothers me dearly!
Yes!!! It is the same for musicians watching actors holding a violin or cello bow with a stiff claw hand or doing vibrato with a jerky movement.