But secondly, and perhaps even more annoyingly, you can't eat anything that died from a crit. Especially for Barbarian, that's rather unfortunate given the assorted crit-enhancing abilities the class has.
Turn off the gib option in the game options menu - then you can eat all killed enemies (I mean kith/wilder/beast of course), no matter how they died (except Dintegration). It's the same with White Worms and Death's Maw and so on: doesn't work on exploded enemies and enemeis that leave no corpse. Gib option is the first thing I turn off - even before turning off companion auto-leveling. It's ridiculous anyway: exploding enemies on crits? Yeeeeah... meeeeh...
Good to know! I don't mind the gibs myself, but it's rather ridiculous that what's essentially a graphical option affects game play in this way. It would never have occurred to me that that might be a factor (though now you mention it, I recall something like this being the case in PoE 1 as well; presumably White Worms there as well, at the least). Presumably the corpses still get gibbed once you eat them though?
This certainly helps for a Corpse-eater, it still needs a more varied diet though. And at the very least, they should also put "turn gibs off in the Graphics menu" in big bold font in the Corpse-eater class description.