Originally Posted by Secret Fawful
If you're running within a time restraint that normally applies to one film, and are trying to write two films in that amount of time, it does affect the quality. Most movie sequels have three to four years in between release - some examples.
Curse of the Black Pearl - 2003 (not bad but could have been much better)
Dead Man's Chest - 2006
At World's End - 2007
Back to the Future - 1985(admittedly the only perfect one to do it back to back)
Part II - 1989
Part III - 1990
Raiders of the Lost Ark - 1981
Temple of Doom - 1984
The Last Crusade - 1989
Kingdom of the Crystal Skull - 2008
Batman Begins - 2005
The Dark Knight - 2008
Batman 3 - 2012
The Matrix - 1999
The Matrix Reloaded - 2003
The Matrix Revolutions - 2003
It usually just depends on the type of movie. The Nolan Batman flicks aren't the greatest example because Nolan always does a film in between the Batman movies to not get burnt out on the characters..... Something Sam Raimi should have done when he was doing Spiderman.
At this point, TTG's BttF Game is the closest we'll ever see to a BttF 4 or 5. There's probably a better chance of BttF getting rebooted/remade by Universal.