For whatever reason I end up playing the Cleric. (Don't tell the folks I play with that I secretly like it!) For the players of more modern games, the Cleric is a heal bot. Which is weird, because there are way more options for customization in 3.X and beyond.
Furthermore, there are good arguments about why you shouldn't put a Cleric class in your games at all. Some folks balk at the religious nature - either because they don't like religion, or because they think it partially blasphemous. Some folks think it's stupid because it's too narrow. Some folks say there are no historical examples of Clerics as they are presented in D&D.
Brother, you can make any of these arguments. If you don't want a Cleric in your game, that's cool, because everyone ought to make the game the way they want to.
But I'm always gonna have Clerics and I think they're just the tops. Let's talk about Clerics for a sec and I'll tell you why I think they're awesome.
1. Clerics can take the place of Fighters, Dwarfs and Hobbits.
In BECM and earlier games including 0E and even Greyhawk, Clerics have the same fighting capability at low levels as a Fighter or Demi-man. They can even wear the best armor. They do however drop off slightly in a couple of places: weapon selection and hit point capacity. The hit point difference is negligible- one HP per experience level on average. The weapon selection is a slight problem in 0E and Holmes because they don't have access to missile weapons. On the other hand, their spells act like missile weapons to some degree.
Additionally, a Find Traps spell, when used judiciously, is the only sure way to determine whether something or some place is trapped. Some early-edition versions don't give Thief guys an extra chance to discover traps (only to remove them). But even if Thief guys and Dwarf guys can find them better, they can still miss one. Every trap you find means fewer chances to either take damage, or Save or die.
2. Their spells are brutally effective on a per-level basis.
Let's take a look at the key level one spells they get:
Cure Light Wounds - Okay, this is useful, but it can basically be replaced by... a potion. You don't need the Cleric to carry this spell. On the other hand, a Chaotic or Neutral Cleric may carry Cause Light Wounds, which is a nice, magical way to affect enemies. Even as a Cure spell, it helps to manage a key resource (hit points) so the party can drill deeper into the dungeon and grab more treasure/XP.
Light (Darkness) - Casting Darkness on the eyes of an opponent is effectively a kill shot. If cast in an area, it will neutralize any advantage the opposition may have from Darkvision. There's really nothing like it at level one. It can do to Fighters and Demi-Men what a Silence spell does to spell casters.
Protection from Evil - Keeping an opponent from touching someone in your party for a period of time can come in handy in numerous situations, and especially when it comes to battles where your Magic User needs to cast a spell, or you need to keep a particular PC alive at low hit points. Arguably, a "Magic Circle" spell is much more useful (hold one evil opponent at bay indefinitely), but for a level one spell, this is very powerful.
And let's take a look at the key level two spells they get.
Bless - This is a mass buff that grants +1 to hit and +1 to damage. It incidentally helps to keep your henchmen from running away in a bloodbath, which should not be overlooked. It works on any reasonable number of creatures too, which means you can gain a lot of leverage by casting it.
Hold Person - Against many enemies you will face underground (and even in the Wilderlands), this can be a kill spell as well. Affecting up to four enemies can swing a whole fight immediately.
Silence, 15' Radius The ultimate kill spell against opposing Clerics and Magic-Users. It can be cast on a person. If the Save vs. spells fails, the radius moves with that person. Cast it on a friendly Fighter, and then send him wading into the enemy to nullify any magic coming from the enemy side! If that's not possible, you can at least hit an area where the bad guys are standing to shut them down temporarily. Do you know what you call a Magic-User who can't cast a spell? A commoner.
3. Don't Underestimate Turning.
Low-level undead are by far the nastiest bad guys you will see during levels 1-6. There's nothing that comes close.
Undead are completely silent and therefore often gain Surprise.
Undead do not parley, and therefore cannot be talked around.
Undead are immune to many spells that affect normal types. And
Undead never check morale. They never stop, ever, until one side or the other is dead.
Turning undead therefore turns these nightmares of resource depletion into a fairly beatable class of foes. Turning may be the single most powerful class ability to have at low levels, with the possible exception of Sleep. But even Sleep is only once per day, while Turning is repeatable.
So the next time you get "stuck" with a Cleric, don't fret about being a heal bot, because you're not a heal bot. Play the Cleric like the monster hunting expert he is and the other players will want a Cleric the next time their hapless idiot dies some gruesome death.