as for me i think he will be defeated in the dressrosa arc for a few different reasons 1.doflamingo is along with mihawk one of the most overated and over wanked characters in the entire series( i remember a poster called him the unofficial 5th yonkou lol)2.ppl keep saying its too soon for luffy to defeat doflaming were over 700 chapters in the series its not too soon(i bet these guys wouldve been saying the same in the alabasta arc its too soon for luffy to defeat a warlord 3.if luffy cant defeat an opponent of doflamingos calibre how the hell is he gonna beat kaido he trained with the friggen first mate of the pirate for two years dont get me wrong it will b luffys hardest fight yet but he will win
all in all i still think doflamingo is a special chaarcter more important than the 1 arc only villians like hody or ceaser but hes been given his dues in the punk hazard arc hes been built up and hyped as the man behind the shadows pulling the strings sorta like croc was from whiskey peak to alabasta there are many more parrallels between doflas saga and crocs saga for example mr.5 and ms.valentine are vergo and monet other posters have pointed out that vergo and mr.5 were introduced in a similar style with a similiar coat and both of them even had there arms in the exact same position theres now way oda didnt do that on purpose i like how someone described crocs interactions with dofla in the war as odas way of having croc "pass the torch" to dofla so again i think dofla is muchmore important than the arc only villians we will learn more about the world gevernment about some of there secrets and history but he will have to be defeated in this arc in order for the story to progress imo