For example, if a DM designs a closed dungeon adventure with a lair guarded exclusively by golems, the casters are likely to be rather "unbalanced" due to lack of opportunity.
Not. Even. Close. If a DM designs a dungeon with a lair guarded exclusively by
golems and the wizards have any clue at all that this is going to be the case then only specialist evokers (already the weakest mages) are going to be slowed by the Spell Immunity.
Almost the entire Conjuration school ignores spell resistance and immunity. Which mean that four the unholy five combat conjurations (
Grease,
Web,
Glitterdust,
Stinking Cloud, and
Evard's Black Tentacles) all work on golems with no questions asked. Stinking Cloud, of course fails because Golems are constructs. But also because Golems are
constructs, they have
terrible saving throws. Of the SRD listed ones, only the CR 16 42 Hit Dice giant stone golem has a save in excess of +6 - and for a CR 10 monster to have saves of +2 and +3 means they are going down like a chump to a low level spell like Glitterdust - even a humble Web will hold all except the big monster a few rounds.
The wizard is laughing at the golems, punking CR 10 monsters that were designed to be his bane with second level spells - and that without using all the versatility @
Victim suggests (must spread XP around...) to simply avoid the golems above.
Meanwhile the fighter had better have an adamantine weapon. Preferably a bludgeoning one. Because otherwise the Golem's DR10/Adamantine (normally) is going to mean that he has problems.
So tell me, which way is this unbalanced? Because by my reading of the actual mechanics, golems are harder for a fighter to deal with than an even vaguely prepared wizard.
If he designs a political adventure where combat is discouraged, the fighter is likely to feel rather "unbalanced", but the bard might suddenly feel overpowered. These kinds of things outweigh the basic action resolution mechanics.
I hear what you say. But in that adventure, the wizard is
still powerful. He just picks a partly different spell loadout. The fighter on the other hand sucks even harder than he did against the Golems.
Edit: The core problem with the 3.X fighter for balance purposes is twofold.
1: When things go outside his area of expertise (fighting) he has no abilities at all to bring to the party other than being a warm body. (Or the Leadership feat...). Literally every other class in the game
including the Barbarian and Paladin has more non-combat abilities.
2: The fighter sucks at fighting. He's good
enough when he manages to get into swords reach of the enemy. But has no special ability at all that helps him get there. He has no additional speed, defences (in fact he has one of the worst saves in the game), way to
not be seen, or any other inherent way to bring axe to face.