Franky will be the one to fight Doflamingo. First, read this thread: http://apforums.net/showthread.php?t=15408&highlight=doflamingo
I believe that to be true. As such, it makes sense that his name is Don Quijote. It's very romantic. For those who don't know Don Quijote, look it up.
Franky is also a romantic person. I am not talking about love type romance. If you read one piece, you should know the type I'm talking about.
Anyway, I think Doflamingo is a spider zoan DF user. He uses invisible threads to move his victims against their will. However, those threads can be burned easily. Seems like a good match up to me.
I think this will happen well into the new world. Anyway, do you agree?