I know you aren't supposed to judge earlier times by your own etc., but whether you should or not, my problem with The Odyssey is all the miserable things done by the HERO of the story (starting with Odysseus and his "war-weary" men finding ANOTHER place to invade on the way home!). I know I started another thread about liking really out-there "anti-heroes," but those are the exceptions in my case, so Odysseus (when he isn't a Kirk Douglas movie character) has always been a problem for me that other violent main characters in mythology somehow aren't.
Since this is a "Monster Kids" forum, one epic to mention (if it hasn't been already) is The Argonautica, which is FULL of monsters.