Marines: The marines are pretty weak, despite their massive numbers. Luffy alone, while at Enies Lobby, took out countless marines[...]
Well duh... of course the marine appears weak if you only consider their fodder and overlook the fighters that really matter; the Admirals, Garp & Sengoku and, to a lesser extent, the Vice Admirals. The Yonkou would appear pretty weak as well, if you judge their military worth by how Mr. 1 carved his way through Whitebeard's fodder.
but Mihawk, who's probably one of the strongest, admitted that the distance between them and Whitebeard, and then pretty much ran away when Shanks showed up.
Sure, Mihawk "admitted" (i.e. he wanted, as I interpreted it, to see how much stronger the World's Strongest Man was) that Whitebeard was stronger. Which is no shame, seeing as the same is true for everyone else in the world as well.
Mihawk didn't turn tail when Shanks appear because he was scared; he left because he hadn't signed up for a fight with Shanks, whom he appears to hold in high regard (perhaps even considering him a friend).
I'll put dragon at the level of Sengoku, but not at the level of kong.
What makes you presume that Kong's combat prowess is superior to Sengoku's, and notably so even?
Personally, I'd think that Kong was on par with the Admirals (and Sengoku) in his heyday, but after declining from age and hard living, is now a little weaker than the colorful trio (but still a top tier).
At least, I'd hope so. We already had Whitebeard as the old man that no one of the younger generations could surpass/equal even when he was old and sick; no need to diminish the powerhouses from the generation of the Golden Age of Pirates (i.e. the current Yonkou's, the Admirals, Dragon etc.) further.
Well, to make a revolution you don't need having the same numbers (Because it's weird then the need of revolution) but having equal strength. Dragon NEEDS to be AS STRONG or STRONGER in order to change stuff.
At some point, yes, Dragon's forces will most likely be stronger than his opposition (if he does indeed succeed in overthrowing the World Government). But for the purpose of the story, he doesn't need to possess that kind of military strength now; Dragon could acquire military strength/support as the series progress.
The manga said Marines=Shichibukai=Youkou. So it's all even[...]
Except that Garp's statement that the Marines, the Shichibukai and the Yonkou are three world power that counterbalance each other doesn't correlate with how the factions respective fighting strength has been portrayed, and doesn't make much sense in the first place since the Shichibukai and the Marines are both employed the World Government.
