Dispensable (?): Divine Casters

At least he hit you so hard you left the battlefield...

     The last archetype to look at is the divine caster. In this case, I am referring mainly to clerics, although anybody who is capable of healing magic qualifies (druids, favored souls, etc). Is it possible to have a successful party without a healer of some kind?
     I might have to say "no."
     Here's the thing: you're going to need some way to patch the party up. Unless the entire purpose of the game is to be low-combat or low-magic, you're party is going to get beat up and you're going to need some way faster than natural healing to get back into the fray. Even the most basic of dungeons is likely to require the party to pause and heal between encounters.
     Now, there are ways you could get around having a divine caster, but I think they're all rather impractical. The simplest solution is just to rely on potions, although it is easy to see how this doesn't stack up to the abilities of an actual healer. For starters, you can't drink a potion if you're already in negative hit points and thus bleeding out. Potions also cap off at allowing 3rd level spells, which means you'll never get that cure critical you really need at later levels. You're also going to find that potions are not as effective as spells cast by actual people, because casters get to add their class level to the d8s rolled for the spell. You could spend extra money to have a potion made at a higher caster level, but that leads us to the other problem. All those potions are going to set you back a fair bit (50-750 gp a pop, and that's base price).
     I've also read about the idea of having a paladin using wands. It's not a bad idea, since anybody with a spell on their list can cast out of a wand, even if they are not high enough level to cast the spell themselves. Wands also let you get up to 4th level spells, which is a little better. These spells will still be weaker than those cast by a cleric, though, just like with the potions. The cost is a bit better if you think about it per-spell, but the wand method of course doesn't have the flexibility of potions (anybody can drink a potion, but only divine casters can use wands with divine spells). Also, it depends on what other role your paladin is playing. Paladins are more martial in nature, and in some ways it seems a waste to have a warrior character wasted having to spend all their rounds running around healing. At least casting is what clerics should expect to do every round.
     So I think I'm going to have to say that divine casters (healers) are the only truly indispensable characters in a traditional D&D party. Again, we're assuming a normal game where combat and traps are the norm, and playing strictly by the rules as given. House rules and games where combat is rare may change this, of course, but that's pretty much true of any rpg commentary.
     As always, though, feel free to comment and let me know your thoughts. Otherwise, this is a wrap on this particular series.