There is some great blog literature about the cleric as a misfit in the fantasy world, and I suggest that you all read it if you get the chance. A good place to start is Delta's discussions of the cleric and how it bothered him throughout the years (scroll down to the bottom of the post).
This excommunication of the cleric would then leave us with three archetypes: the warrior, the scoundrel, and the magician. Three is a nice number. It lends itself well to overthinking and false analogies. The following may or may not be one of those.
Warrior, Scoundrel, Magician = Present, Future, and Past
The warrior is living for the glory, the thrill, the power. But the warrior's glory does not come after the fight, it comes during the fight, as he (or she) is flaying the dragon, beheading the minotaur, or stabbing the orc general. His strength and potency comes from what he can do right now. A general without an army to command right now is not really a general.
Warriors are typically depicted as men, in the real world, and even in fantasy. There are a host of stereotypes that explain this, but perhaps one of the least examined is the correlation between the male brain and mental focus: paying attention deeply to one thing is emphasized, but planning ahead and multi-tasking are underutilized.
I would argue that the warrior archetype is inherently uninterested in planning ahead and multi-tasking. It doesn't mean a warrior can't plan, or multi-task. But there is something about the warrior culture and warrior mindset that implies addressing problems as they arise with whatever strengths and strategies become available in real time.
In game terms, this means the warrior excels after combat starts. Once each combatant must begin making decisions and acting on them, the warrior is most in control. This means being reactionary. But very effectively so. "He does A, so I respond with B. She does C, so I respond with D." That kind of cause-effect reality means warriors are inherently focused on the present in order to be effective.
The Scoundrel, on the other hand, is most effective when they can predict what challenges lay before them. This can be boiled down to the mind-numbing mundanity of "I search for traps," but it also exists at all the other levels of interesting play. Cat burglars and art thieves stake out their targets to better predict what they will be up against. They set up road-side robberies as chests of gold are being transported from the royal coffers.
Even combat oriented scoundrels are focused on setting up a future opportunity to strike for maximum effect.
Scoundrels are the ones that walk away with the gold, avoid consequences, disappear into anonymity, etc. That doesn't happen on the fly, it happens because these archetypical characters are constantly planning. "If he does X, I will do Y. But, if he does W, I will do Z." A scoundrel's mind must always be playing with possible future worlds, and planning not just the next move, but the next three moves like a chess grandmaster.
The magician exists in the past. A magician's influence depends on what archaic secrets of the old world they can master, and what incredible shifts of reality they have accomplished. The magician is potent not based on how they can react to what their enemies are doing, nor how well they have planned to deal with their opponents' strategy. A magician is powerful based solely on what they are independently capable of. If you can incinerate a man at the flick of a wand, the most important part of your development as a magician was not the moment of incineration, nor the plan you concocted to find and incinerate that person. It was the moment you figured out how to incinerate someone. The sheer unpredictability of your powers is, in itself, dangerous.
"I have amassed this power," the magician says. "Try and stop me if you wish."
This makes the magician sound like an evil archetype. And it sure as hell works for evil characters. But it can also be a force for good. Unless you live in a world that has entirely collapsed to evil, then evil must have been defeated or staunched in some way before, but you can only find out what those methods were by looking to the past.
This tripartite comparison creates its own rock-paper-scissors relationship as well. Warrior is reaction, magician is unpredictability, and scoundrel is prediction. The warrior beats the magician, because the only way to beat something that's unpredictable is to react efficiently and effectively at a moment's notice. The magician beats the scoundrel, because if the scoundrel cannot predict their opponent's capabilities, their advantage is lost. And lastly, the scoundrel beats the warrior, because it is trivial to predict something that works on a basic cause-effect, action-reaction formula, and it is therefore easy to counter.
Yet another insight from this comparison is what it has to say about the magician and "game balance." I'm not talking about balance in the sense of "the magician shouldn't deal more damage than the warrior" or "shouldn't roll higher stealth checks than the scoundrel." Rather, I'm talking about giving your players and their characters roughly equal time to shine in any given game. Warriors are best at reacting to sudden events, and scoundrels are best at planning how to circumvent the better part of the challenges they can predict. The magician should be pure, raw magical effect.
But if you let the magician prepare too accordingly for the challenges they will face, then it begins to overshadow the scoundrel. Who needs to sneak around the frost giants and set their fortress on fire if the magician has a dozen fire spells prepared?
By the same token, if you allow spells to become too utilitarian, and give the magician too many of them, then they start to overshadow the warrior. Oh, the demon has summoned two fire beasts? Well, my wall of iron will keep them at bay. Now the demon is trying to disintegrate my wall? I cast arcane transference and absorb his spell, then use the spell slot I gain from that to cast sonic boom against the crystal golems, which is an auto-critical.
See what I mean? Old school magicians, with their tiny spell lists and laughable number of spells per day were like a shotgun: effective when used for its intended purpose, somewhat effective if used for a well-thought-out improvised purpose, and disastrous if used for anything else. Sure, you can shoot an enemy with a shotgun, and you can even blow open a locked door with a shotgun, but you can't put out a house fire with a shotgun, and you can't create an anti-venom with a shot gun. During those times, other characters get to shine.
But the trend in magicians has been to transform them into a Swiss-army knife/multi-tool/Skeleton key archetype, where they can steal the spotlight entirely, so long as they do their research and prepare the right spells. Not only is this unfair to the players who want to make characters that aren't magicians, but it also is opposite the original feel of the magician. Archaic and arcane secrets aren't a dime a dozen. In the LOTR movies, Gandalf was away for over a year doing research and hunting gollum just to learn about the history and tell-tale signs of the One Ring.
In the books, that quest takes him exactly seventeen years. I don't think that much time should be necessary to discover some arcane secrets, but you get the drift.