As per the title I am wondering this:

Why many people ban Wizards and Clerics?

Even when they run high power campaigns with 32+ point buy, 6m5d6r1v2 stats generation or even gestalt characters they ban them.

Admittedly I don't have big experience with a lot of D&D outside the core books but I don't see how they could get overpowered if the DM keeps them on a short strain. (e.g. Kobolts "happen" to attack the time the Wizard sat down to study his spells or the priest raised his hands on the night sky to pray for spells.)

Simple: even with such attempts at restriants (which if they work mean the guy is completely useless for the day. If they don't, then it was wasted effort, and either way, it's an extreme annoyance to the players), they can easily break the game. Most players won't try to break the game, but the fact is that the classes are inherently powerful on account of literally having access to thousands of spells to choose from on a daily basis. The only way to make sure that it doesn't happen is to ban the classes, especially in PbP where you don't know who is a munchkin.

However, I assume by "Priests" you actually mean "Clerics and Archivists" since there is no such class as a "Priest" in 3.X. The other members of the Big 5 are usually:

A. Druids are often replaced with Shapeshift Druids or some other variant without Wild Shape. They also have a huge repitore of spells to choose from, but these are usually less powerful.
B. Artificiers are more often banned on account of being Eberron material
C. Eurudites are most often banned because they're psionic (nobody turn this into a "psionics should never be banned" thread)

having access to thousands of spells to choose from on a daily basis.

Well that just reminded me of the debate I often had with my DM's as wizard - which spells I had access too. The fact that was starting as 5th level wizard didn't make me know 14 2nd level spells for example. Usually, when starting as 5, I d knew about 5 or 6 2nd level spells.

Note here that we house-ruled away the rollplaying rule 2 new spells per level. A wizard learns spells by studying arcane magical writings, ie spellbooks, and scrolls. That way when there was a scroll on the loot it was merely a useless levitate scroll but a scroll that would enable the wizard to learn the spell (making it more fun) - and of course the PC was restricted enough so the DM had control over him. (Imagine trying to buy a scroll of fireball from the mage guild of the city and them offering Protection from Energy ...)


P.S. Yes that priest thing was meant to be cleric, I ll see if I can edit it.

Wizards (and Archivists) RAW can copy spells from scrolls into their spellbooks anyway.

1. What does RAW mean?
2. I m not referring to Archivists (have 0 gaming experience with them) only to Wizards and Clerics.

But finding the desired scroll need not be as easy as finding bat guano.

Rules As Written.

o ok

In that case we said the same thing about:

Wizards (and Archivists) RAW can copy spells from scrolls into their spellbooks anyway.

I m not arguing that Wizards are as balanced as a Fighters, I m just saying I do not see/understand why people are so dead set against Wizards and Clerics being in their campaign. They may be right, I m just asking to learn more about it since Wizard has always been my favorite class.

The most unbalanced sourcebook in all of 3.5 is the Player's Handbook. In the expanded game, the most powerful classes, the Big Five, are Archivist, Artificer, Cleric, Druid, Erudite, and Wizard. Note that half of those classes are from core. Further, much of their most effective abilities are core as well. Through dozens of additional sourcebooks, and a quintupling of available base classes, only three classes manage to stand at the same level of raw power as the Cleric, Druid, and Wizard.

On the flip side, core melee is tremendously underpowered in a manner that's been discussed extensively and repeatedly, making this imbalance painful on both ends.

To make the game balanced, you need to do something to bring down the mages and bring up the melee types. To redesign them all manually is a vast amount of work. The simplest way is to simply cut the Gordian knot. See, while the Big Five are broken, the other casting classes are generally fine. Sorcerers, Beguilers, Favored Souls, Psions, all are pretty fair. By cutting out the casters with access to hundreds upon hundreds of spells, the more reasonable classes with access to a few dozen spells remain as more reasonable alternatives. The standard fix for melee types is to bring in Tome of Battle as a replacement. While a fairly normal Wizard walking next to a fairly normal Fighter is horribly unfair and will result in the Fighter being a waste of space at mid-to-high levels, a Psion next to a Warblade is considerably more fair.

Further, banning Wizards does not ban wizards. There are no fewer than eight other classes that can be used to represent a character who is a wizard, without the use of the Wizard class, and literally any class can represent a character who is a part of the clergy, so cutting the Gordian knot does not hinder any character types, save Artificer which is tough to replace, but that's Eberron-only anyways.
This is not a solution in any capacity. If you're deliberately doing this to hinder a player, it's a case of specifically turning to one player and saying, "Up yours." When you have to pull stunts like that, there's a problem.
It's more that they're ill-defined and don't actually exist; they're just an appendix from the back of Complete Psionic, and they have a lot of cheese available to them.
The DM does not have control over which spells the players have access to without usurping the rules, as players are allowed to spend their gold however they please within the constraints of city wealth, and there are rules on the pricing of spells. Copying a spell to your spellbook costs 50g*spell level, which is a very low price and allows the Wizard to attain hundreds of spells.

If the DM does take control of the Wizard's spell access to maintain balance, that means the DM has to do it manually and balance is not available by default rules, and that the DM has to put every spell the Wizard seeks to acquire on a scale first and decide whether it's balanced or not on the fly, which is a bad thing. It oftentimes results in the Wizard saying, "I spend my money in a perfectly legal manner and spend the afternoon learning another spell," only to have the DM respond with, "No, I refuse to allow you to take that perfectly legal action," whether by refusing to provide a place to acquire the desired spell, or forcibly interrupting the Wizard's study, and oftentimes leads to the blatantly unfair situation of refusing to allow the Wizard to legally purchase a 200g service while dropping a 20,000g sword in the beater's lap.
Fighters are not balanced, either. They're hideously underpowered without extreme twinkery after the first few levels, and largely form the flip side of the game balance problem.

Well, thanks for the detailed reply. I appreciate it.

I lol'ed

Now on the subject.

The DM does not have control over which spells the players have access to without usurping the rules, as players are allowed to spend their gold however they please within the constraints of city wealth, and there are rules on the pricing of spells. Copying a spell to your spellbook costs 50g*spell level, which is a very low price and allows the Wizard to attain hundreds of spells.

That's not always the case. Taking an example from real life.

A semi automatic pistol costs X amount of money but not everywhere in the world you can go to a store and buy it. Someplaces you can, in some you can't unless you are a policeman, have special licence or got to the black market and buy it a overpriced.

Or to make an example from a fantasy setting.

A 15th level duergar wizard who found himself in Menzoberranzan (FR campaign setting) cannot just walk in Sorcere and buy a scroll of prismatric ray despite it being well within the city's and his own wealth. He 's far more likely to get killed than get out with the scroll. Neither is such a scroll likely to be sold to anyone in a shop open to everyone without a ruling house pulling the strings behind the scenes. The duergar wizard may have to do a "favor" (ie minor side adventure) for Bregan D'aertha so they can acquire the scroll for him for a little extra gold (say 20% above DMG price).
And spells like magic jar may well be out of limits even in those scenarios. Such a usefull and strong spell may very well be accesible only to the Arch-Magister of the city and a select few other Master-Wizards. Nothing within the rules compels them to write a scroll with it in and sell it. Neither they forbid them from taking "pre-emptive measures" that such a scroll is not accessible to anyone (namely any fool who will think that he now is strong enough to kill them in order to take their position). If you however somehow get in contact with the Arch-magister and do a dangerous "favor" for him he may sell you a scroll of the desired spell (at DMG's price).
In my opinion [I may be wrong ofc] that's hardly (a DM) usurping the rules in a role-playing game such as D&D.

The wizards and archivists can reasonably be controlled only to an extent. You have to figure that even if the Wizard/Archivist can't buy a scroll or find someone who is willing to let them copy the spell, they can still research the spell independantly, thus get what they want anyway (or use a stolen/formerly owned spellbook). Then there are the free spells every level that they get. Denying them the ability to find the scroll in a shop really doesn't mean much to them as if they really want the spell, they will get it anyway.

And of course, Clerics just have auto-access to thousands of spells anyway.