@Angel:
Bounties: not power level. Robin's is a reflection of her knowledge of the ponegylphs. All that happened at EL is her photograph was updated. She is still just as dangerous as before. And Chopper wasn't seen as a threat at all.
Hell… When it comes to that, the Shichibukai bounties are not a reflection of their power level as their all bounties were squashed. Their former bounties, as in they don't have them now. That means, they should have a power level of "0" if it was based on power since they have "0" current bounties. Shichibukai former bounties also don't reflect the current strength because the WG and Marines haven't taken anything they've done since joining into account.
And if it truly is a reflection of power Luffy and Cos bounties are also not a true reflection - neither Kuro's fight nor Skypiea have played a part in increasing their amount since the WG and Marines don't k now they happened. So none of the SHs bounties are correct. Hell, Oda said Enel would have been 500,000,000 if he had been known in the Blue Seas. Think how that would have effected the SHs bounties.
While yes, you're thinking is correct. You are being blinded by it.
While all unknown bounties are 100% unfounded (especially frozen ones) bounties like Nami's, Zoro's Luffy's, Sanji's and Franky's are definitly able to tell us something, because their bounties were issued soley on the means of combat strength.
Yes, I'm sure some of the bounty is simply because they had the balls to attack EL, but they all got different bounties for a reason.
So yes. I'm gonna compare Brooke's and Franky's (even though we don't know what Brooke did). The fact that I (and several others) predicted a 14 mil range that it would be in (and it was) proves that bountys are more predictable than you're saying.
I'll be the first to yell at anyone who says Usopp can beat Arlong because Usopp's bounty is higher, but by estimating Brooke's combat strength to be AROUND Franky's and Robins? I'd say that's legit.
P.S. I actually do support the Usopp beating Arlong theory (but not because of bounties)