So, J.K. Rowling should create a movie going into depth about Dumbledore’s life. There’s only so much that we, as fans, know about him. Even Harry didn’t fully know him or his life.
A few things we do know: He was friends with Nicolas Flamel. His password to his office is Sherbet Lemon. He owned the elder wand. He can apparate anywhere he damn well feels like. He once got a vomit flavored Bertie Bott’s every flavor bean. He has a brother and sister - but there is little known of them as well. (Please, feel free to add to this list.)
It is possible to look things up on the internet to find these things out, but it is all still very vague. Even after reading what was in the links, it kind of just fueled our curiosity more.
Albus Dumbledore & Gellert Grindelwald
Example: Take your grandparents for instance. They have told you many stories about their lives, and can even go into detail. You picture all of this in your head, but you weren’t there, so you kind of don’t know how it all was. There is a part of you that wishes you could be there to witness it.
So, while the actors are still the ages that they are right now, it would be a good idea to get Rowling on board with this idea. Of course Daniel, Emma, and Rupert would not have to be involved with this. Just the people that were involved in Dumbledore’s life from the beginning, to watching Tom Riddle transform into Voldemort right before Harry was born.
It would not be to cash in on yet another Harry Potter movie, but to give fans a better visual understanding of the story. Just like Pottermore and The Tales of Beetle the Bard, this is just another way to clarify and expand the story to make you feel more involved as a fan of the Wizarding World (and add some closure to fans that are sad that it is all finally over with). Just read these links and tell me that wouldn’t be awesome.