I never saw it as a problem that casters at higher levels are stronger than non-casters.Pilgrim wrote:But in doing so, you break the balance between classes. Magic-users have to gain more XP due to the power they wield, thieves level faster than other classes. The balance between classes depends on this differentiation between levels to keep things in check. By leveling the entire party at once, the magic-users will be gaining access to their spells, but in scale, the other classes will now be falling behind because they are no longer gaining the advantage through faster level gain.
This is one of the reason players of 3.x have such problems as parties gain levels above 7th, with the unified leveling that 3.x introduced, there is no longer an XP/level buffer in place to keep casters from overshadowing other classes.
First: it's give-and-take, the wizard wouldn't have survived the first goblin dungeon without the reliable warrior, and now the warrior needs help from his fellow magic-user to deal with balors. It changes the experience, from "SHIELD CIRLCE and PROTECT THE 3HP ELF!" to "QUICK! SOMEONE CAST STONESKIN ON THE BARBARIAN before he gets cut to pieces!".
Second: I think that 3.x higher level characters are supposed to multiclass in some caster class - be it cleric, wizard or a prestige class. D&D 's about "sword AND sorcery", not "OR sorcery".
And I don't really think a level 20 wizard could go SOLO in a dungeon any better than a 10 Warrior / 10 Cleric would.
I know a wizard would always have that timely FLY, or PLANAR DOOR, or TELEPORT or "save-my-skin-now" spell to get out of trouble. But I suspect most wizards would rely too much on their spells, and so they could be caught off guard (antimagic circle, anyone?? ) , while a warrior or a barbarian KNOWS the perils of the world better, I think.