Partly in response to Edward's response to Rachel's distaste for the cleric.
To the degree that I have read her material, I mostly agree with Rachel. The cleric is important to gameplay, though I would argue that the importance of turning is often underemphasized compared to spells. I see turning as the cleric's primary / core 'encounter-win-button' ability - the first-level mage can sleep, the first-level thief can backstab, and the first-level cleric can turn those foes who are immune to sleep, morale, and stealth. I also believe that the cleric serves an important social function as the advocate of morality, per Roger's post here, as a balance to the thief, who advocates for selfish action in the party's interests.
So they have their uses... but I concur that the standard light-sun-and-law gods, to which clerical spell lists typically default, are rather dull. I suspect that there are a handful of reasons such deities are standard-issue, rather than say the jealous and fickle gods of antiquity, or Moorcock's cosmic Law vs Chaos from which D&D derived its alignment terminology. First, the influence of the Hammer Horror films on Arneson has been noted as a probable influence. Second, the influence of historical Medieval literature, with its Christian religious themes, and Tolkein's work, with its thematic struggle between light and darkness (both in the Silmarillion between Morgoth and the rest of the Ainur, and between Sauron and the forces assembled against him). Finally, there is the fact that the game was developed in the USA in the 70s. Even in the 70s, it was still 'Murica (particularly in Wisconsin), and even if the game's authors didn't buy into Zoroastrian-style cosmic dualism, their players and the rest of their communities probably did. Cultural context matters.
Finally, alternatives. I like the divine elves idea. A lot. Part of this is because I like Midnight, and part is that I feel that nature/star-driven divine magic suits elves better than arcane magic does. While capable of maintaining the mechanical functions of the cleric, the divine elf does suffer from the lack of necessary moral superiority for the social role of the cleric as "shepherd to the flock". It would also be fun to take the "multitude of minor and confusing gods, each with many aspects" approach from the Wilderlands - every cleric gets his own deity, and random rolls for the spells his patron can provide! Players choose deity name and flavor based off of any emergent trends in rolled spells. Dark Heresy's priest is really more like a bard, which might be a reasonable interpretation of how religion works in some settings as well. Or what I've been doing so far, which is just rolling loads of specialty cleric subclasses...
The trouble I always sort of expect to run into with any such change to the cleric is resistance from players. Which upon further reflection seems sort of silly; how many players bear so much affection for clerics that they would object to changes thereto? Given that my current party has only one normal cleric (and he's a henchman) but three non-pseudo-Catholic cleric variant PCs (bladedancer, amazon, and sea-priest who had to drop), I begin to believe my concerns are unfounded (though I have heard grumbling from some of the fighters about 'None of these clerics can wear plate! We're doomed! The line cannot hold!' Which is patently ridiculous, considering that for the first 75% of last campaign, they lacked any cleric at all, steel-clad or no, and the line usually held...). For what it is worth, I vaguely recall Alex Macriss of Autarch mentioning on the fora that one of his regrets with ACKS was keeping a standard cleric in Core and shamans and witches in the PC, rather than going for alternative divine casting in Core for a default "sword and sorcery and sandals and Thulsa Doom" sort of feel, with the reasoning being that "it's a retroclone, it sort of had to have a cleric."
So smash all your idols, and build anew! Therein was the thing that bothered me in Edward's post - suggestions strictly for the use of published material, rather than a new and strange idea yet to be built. Go forth and create!