Just from a 1e perspective:
Quote Originally Posted by Sam View Post
Eating souls gives you xp benefits- after all, why do you think you level up after killing things? You are consuming their lifeforce!
An interesting interpretation, and one I can see Evil deities promoting, but you get xp for other things, even in 1e. Are you sucking out the lifeforce of all that gold too?

The good/evil spectrum should have benevolent and vile. Benevolent are people who go out of their way, looking for ways to help. Vile individuals are psychopaths- evil individuals are callus towards the value of some people's live, but vile people are callous towards EVERYONE. Individuals on the extreme ends gain greater power in their respective spells, but the evil ones are more vulerable to good magic.
This seems fairly BtB to me: good is benevolent (in the extreme, self-sacrificing), while evil seeks to deprove others (in the extreme, murder and human(oid) sacrifice).

People's status in this world translates into LE afterlifes, making working for the evil gods a viable career option. Pledge yourself to Hector in this world and he will give you a legion in reward after your death. Unlike good afterlifes, you can gain a large amount of sheer power.
Well, that's what they tell YOU. In reality, most evil deities don't want to share power, especially with anything as dangerous as a high-level PC! Much of the time, their worshippers are tools.

In my Greyhawk campaign, the suggestion you made is more relevent and I view the gods' aim as wanting to "harvest" lifeforce in preparation for some sort of showdown with the other gods for control of the gameworld. Higher level souls are worth correspondingly more power. After the showdown, the world will become monotheistic (or at least mono-pathenionstic if there is such a word) and the struggle will move on to the next parallel PMP. The druids' cabal works to prevent this and to ultimately expel all gods from the PMP.

I had some ideas for really evil deads, but due to the availibility of magic AND afterlives, it is sort of useless. Why organ leg when heal and shapeshift spells are available?
Well, in 1e these things are rare so it's still a possibility in, say, cities. I seem to remember a short story on the topic in the Dragon once, many years ago.