Liu An, I must say, had neither intelligence, courage, filial piety, nor true loyalty (or whatever you want to call it) to Liu Bei. It still amazes me that the Mao father and son team decided that it's good material to stick in Luo Guanzhong's manuscript.
I say he had no intelligence, because he didn't bury the body after the act (maybe he was planning to cannibalise the rest of it later??), and left it to rot in the kitchen (which was where Liu Bei found it). Perhaps he meant for it to be there when Liu Bei went to fetch his horse?? That makes him reeeeallly devious and I'm not sure that's the image that the editors wished to promote. He had no filial piety, because, first, who's going to take care of his elderly mother when his wife's gone? And what would his mom think of his murdering his wife? What if his mother went into the kitchen first the next morning, and gets a heart attack? Furthermore, it's not clear that he had a son yet. Who's going to carry on the family line (He couldn't be counting on a reward)?
There are also better examples of "cannibalism" for the sake of one's lord in Chinese history. Jie Zitui (of the Spring and Autumn period, I think) was fleeing the country with his lord, and his lord got hungry. Jie couldn't find any food, so he cut off some meat from his buttocks (or thighs) and cooked that for his lord. Now *that* is courage and dedication to one's lord. Sacrificing someone else is not.