there is also the scourging light of heaven that will burn or destroy anything that is not 'pure'. most earth villains would be slain by this power alone. there is also the fact that no mortal can touch an angel (a true angel, not one that has assumed flesh) without burning. low level heroes would have a tough time with this. their swords can cut pretty well anything and are said to be particularly effective against magic. an angel's scream liquifies stone and metal. 6000 of these bad boys would be a problem. don't know if molecule man (that guy is so f'n lame and ruins these VS marvel earth threads!) could survive the light of heaven or not - he certainly isn't 'pure'.
and there's the question of who is leading the host. do they bring down a king angel? THAT would make a huge difference.
i'd say earth could pull it off, but there would be a LOT of casualties. if a king angel comes down with them (especially one that is full-powered), i'm not liking earth's chances.