1) The revos have already stated their target are the Tenryuubitos and the WG, not the Marines, they have nothing against the Marines, Dragon is not interested in bringing down the Marines, he targets the man that stands at the top of the world : Im.
2) Im will never compare to Blackbeard as a FV candidate, not only just because he's been introduced far too late and will probably not meet Luffy until the very very end of the story but also : This is a manga about PIRATES, Luffy's dream is to become PIRATEKING, not to bring down the WG.
Will Luffy still play a role in the war against Im? Sure he will. But that is NOT part of his dream, Blackbeard is the man that stands between Lufy and his dream, Blackbeard is Pirateking material too, he will be Luffy's greatest rival and foe, his ultimate nemesis.
Also Im going down AFTER Blackbeard doesn't mean that makes him the FV, chronogical order doesn't mean shit, BB can go down earlier and still be THE most relevant villain in OP.
3) Akainu is a much better candidate for Luffy to fight in that final war, Akainu is the man that killed Ace in front of Luffy, that gave him his scar, that mutilated Jinbe, he is to this day the only man Luffy has shown hatred for just at the mention of his name.
For those who think Sabo will fight Akainu, that's not likely at all, Sabo was not at Marineford, Sabo didn't go through any trauma.
If Law didn't get to beat up Doffy who he had far more personal business with and history than Luffy, then why would Sabo get to beat the ONE GUY that Luffy really wants to take revenge on? This also apply to Wiper or Paulie who didn't get to beat up Enel/Lucci.
4) Dragon is the man of CHANGE, not Luffy. Luffy will be Pirateking, greatest pirate ever and blablabla BUT as I said before, his dream isn't to bring down the WG and to change the world, that's Dragon's dream. Dragon is the symbol of revolution, Dragon is the leader of the RA.
Dragon and the RA will bring down the WG with the help of the Pirateking, NOT the other way around, this is the RA's fight first and foremost.
