And yeah, I know I'm late on the reply. Couldn't help but answering.
Anyways, cut the Shichibukai level crap. THEY DON'T HAVE ONE. It's a force that if gathered, equals the Yonkou, or gathered+Admirals, or anything like that that's maintaining the balance. You can see Mihawk for perfect example. He might beat Shanks' in a fair fight, but hey, he's a shitty Shichibukai.
Also, we don't know anything about WB or Doflamingo, so how can you say anything about a fight? Hell, we can't even point Ace's strength other then the 2nd division captain thing, and that's not enough.