I agree with pt_peach on the 50 year old sequel thing. Why??? Do they just say..."Hey, while we are waiting for our next big picture, let's rehash one of our classics and ruin it with a sequel!?" Honestly, you never take a great film which told its story in full and make a sequel out of it! The only exception is if you can come up with a grand, million dollar plot that's sure to guarantee a blockbuster. These people have too much time on their hands.
Another issue is the millions of sequels they've made about the "Land Before Time" series. I loved the first sequel, and the second, but now they've made about 10 of them. Another question I pose is why the heck would they make two sequels to An American Tail: Fievel Goes West 10 years after it's original release date?