I'm not sure I'd call Loki a God. He certainly isn't of the Aesir according to most variants of Thor comics. Really Loki isn't that tough, his power lies in staying out of reach, failing that, he's a divine punching bag.

Don't get me started on Superman... The sad thing is, I've actually always liked Superman comics and JLA stories. His character is solid, it's just his powers that make him so damned boring. It should be noted that there are much better written Superman comics in which he isn't all powerful and actually can be beaten by people who don't keep kryptonite in their pants. Darkseid and Doomsday have both kicked the shit out of Supes in various stories. But Superman isn't even the worst offender in DC. Batman is. No powers. Beats Superman every time they fight. Takes Darksied down without throwing a punch. Can defeat the entire JLA with minimal planning. Can walk out the front door after being captured by the Legion of Doom... Batman wields the power of plot, before which all abilities are meaningless.