Yeah, like, T'Challa alone could put Annihilus in a headlock or something.
Dead horse: BEATEN!
Really, though, I don't think Earth could win. It's not like outer space was skimping on superpowered soldiers to throw at the Annihilation Wave or something. They had Nova, Quasar, Gamora, Drax, Ronan, the entire Kree empire, Galactus Heralds, Galactus himself, and more besides, and even then it wasn't the actual resistance itself that turned the tide but betrayal from Thanos. At the time of Civil War, Earth had a total of two active cosmic-level superheroes: Sentry and Dr. Strange. And Sentry, as we know, is a useless living toilet. There was...let's see...one omega mutant even remotely near full potential, which was Iceman, who is also a useless living toilet. Jean was dead, Xavier was powerless, Cable was at half power, Hulk was away, Thor was dead; the most powerful heroes that Earth probably had to offer at this point were Iron Man and Namor, who are -- at best -- maybe as powerful as Ravenous, who's just a henchman. Earth's military is a joke compared to almost every single alien culture in existence. The only thing Earth really has as any advantage is its high number of largely B-class non-cosmic heroes and even then the Wave would just overwhelm with sheer numbers. The only way I see Earth being able to win is through sheer Comic Book Against All Odds Victory (which is kinda what won it in the original too, it has to be said), probably by some Reed Richards deus ex machination.
