I know Osborn had one sided prep, but shouldn't Asgard have some defenses?
You would think they would have guards and tech to alert them and have some sort of battle plan in place. They were all (king, best warrior, most powerful warrior) taken out in like three minutes. Even when Surfer attacked there were guns fired on him. These are warriors around for thousands of years. Thermyscira, New Genesis, Shi'ar homeworld, JLA Watchtower or, hell, even Medieval Times in New Jersey wouldn't fall like this. Hogwarts had some defensive spells around it. You'd think the biggest magic users around would at least get a three headed watchdog. Even a castle in the Middle Ages with street level archers would have put up a bigger fight.
Seriously, what's up with that?
They probably had more pressing matters.
Plus unlike trolls humans are awesome