Wik said:
If arcane casters could only cast from, say, Necromancy, Enchantment, and Divination, would they really be WEAKER than their unlimited counterparts, or just different in focus?
They would be weaker, with out a doubt. Being limited to those three schools means a less versatile character. Undead are Immune to Enchantment. Necromancy, while it has some nice spells, has quite a few very specialized spells, and lets face it... a lot of people object for pure taste issues on animating corpses. Clerical Divination spells are more potent and useful than Arcane Divination, and if you look through the supplements, you will find the most neglected school is Divination.
You are also increasing the amount of work a Wizardly or Sorcerous player has to apply to making his character 'effective'. In the example given of no Fireball but there is Lightning Bolt, the quintessential area effect spell is removed. Unlike Computer D&D games, I find monsters rarely queue up in a line. Thus by effect you are encouraging builds with Arcane Thesis Lightning Bolt and the Widen Metamagic feat.
Of course players have to have the knowledge and the time to research, devise, and plan for such contingencies, and conditions. Conditions their warrior counterparts do not have to go through.
Think about removing all Martial Weapons from the game...would a fighter or barbarian be impacted? The answer is yes.
Would it destroy the game. The answer is no, because at it's heart D&D is a shared creative activity, and as long as people buy in it works, but it might hurt someones enjoyment.
I personally love Teleport spells, I love the fact the books like PHB II have more limited Teleport spells like Regroup, or reactive short range Dimension doors. Something about Instantaneous Molecular Transport just tickles me...dont ask me why. So while I would play in a game that did not allow them, some of my enjoyment would be diminished.