There is definitely something to be said for those brave enough to take the scariest step of all and build on a classic. I am speaking of the treacherous world of companion novels, a field considerably more dangerous even than simply writing a completely original work. Why?
Because it is so easy to fail.
Companions are risky because they attempt to build in an already constructed universe. These writers take well known, well loved characters and attempt to carefully place them into an entirely new storyline, taking all the character's baggage with them. No wonder so many fail. There have been several attempts at successfully continuing the adventures of everyone's favorite pipe smoking detective, but avid Sherlockians will pounce viciously if Holmes so much as steps a toe out of character. And don't you dare mess with Watson.
And yet more and more writers, including screenwriters are attempting the mine field of continuation. Many suffer the flames but a few have pulled into an interesting flair of success. While Ripley's Scarlett, a continuation of Gone with the Wind, fell flat on its intentions, Tim Burton's screenplay continuation of Carroll's Alice in Wonderland has met with great commercial success. What is the formula?
Tim Burton did have a visual canvas to recreate his story but that doesn't change the hazardous conditions. He was still charged with creating a new story with characters that still rang true to their original form. A difficult task for any writer. Burton got around this but simply adding more dimension. Yep the Hatter is still mad as well as hatter, but now he is brave, the leader of a rebellion, a protector. But the Hatter is still true to form, slipping in and out of lucid sanity on the screen. Even Alice, who is portrayed as thirteen years older must keep to certain standards. The new Alice maintains her sense of wonder and curiosity, her disbelief in the world she has landed in, while also allowing for character growth and development. It is a fine line to walk, and although many people have enjoyed the new story of Alice in Wonderland, I haven't heard anyone say it is better than the original. This is another consequence a writer must deal with in this particular category. Writing a true sequel to a work that has become a well loved classic always comes with the price of being held up to the original masterpiece, most likely the reason most companion novels do not fare so well. Still there are always exceptions, which is probably why writers keep trying.