Or he can increase the prices, or reduce the power-level of his own rule. He doesn't have to rewrite the game.
No, he just has to rewrite the economy of D&D. Second option depends entirely on whether it's necessary.
He's already done that, by creating items that the DMG would price at 100k or more, and valuing them at 1gp.
No, he cannot. Wizard time stops and gates in 1d4+1 epic monsters. For starters. Then there's also shapechange, contigency, undead hordes. Forcecage is just 7th level and will auto-beat the warrior (even AMF can't remove the wall of force).Trivia, you knew wizards actually have an high level spell that allows them to cast inside an AMF? Or the cleric of mystra that simple laughs at AMFs? Meanwhile any melee build will probably be an unbercharger or lockdown, and they'll always outmaneuver the warrior because they have magic items. They get the first hit dealing hundreds of damage, warrior dies.
It comes down to initiative. A warrior with a bow can disable as many wizards per round as he has attacks, if he goes first.
I have learned something from this response, particularly the part about every build being an ubercharger or lockdown -- you're used to playing in very high-powered, optimized campaigns. Even in such a campaign, I think parts of your rule are problematic. In "average" games, it's worse. It's not easy for an average D&D player to create an effective ubercharger, or even an optimized caster. It's very easy to create a straight fighter with a few pure metal items. Using them doesn't require any difficult strategy -- just load up with pure metal arrows, and fire them at every spellcaster you see. Or cripple both of a melee character's legs, and then stand back while he tries to drag himself to you on his elbows.
I've seen worst. You know what bogs down gameplay? At-will arcane sight, which I've seen quite a bunch of people around here put on their homebrews.
Yes. Many things, particularly some spells, can bog down gameplay. Even iterative attacks can be a problem. No reason to create new things that do that though. It might be worth spending a little time to see if you can come up with a simpler rule that still has the power level you want. I'm too tired to come up with one myself right now.
Basic dagger is 2 GP. Double it for cold iron, 4 GP. Double again for pure crafting, 8 GP.
Meanwhile casters didn't pay a single dime to get defensive casting in the first place.
It seems like you're saying that the price is reasonable because it's 8gp, not 1gp. Sure, it's 8x as high, but 8gp still isn't very much. And fighters didn't pay a dime to be able to grapple or bull rush. Monks don't pay a dime to flurry. It doesn't make sense to say that class features and core rules, being free, should be priced at lower than 8gp.
I'll admit the core spells of the ranger/paladin aren't very hot, but there's plenty of cool powerful magic in splatbooks for those classes, in particular when combined with that option for paladins to cast their spells as swift actions.
I'm arguing that pure metal items, even cheap ones, are more powerful than the entire ranger and paladin spell lists, even with splatbooks. Do you disagree? I mean, is there a ranger spell which doubles your armor bonus, doubles the attack bonus from your BaB, makes you almost immune to magic, and lets you completely cripple an opponent's spellcasting ability with a single attack?
Leadership, Item Familiar, wild companion and friends would like a word with you.
You might be right about leadership, but only because your followers can craft pure metal items. You're basically giving a 99% discount on powerful item abilities. I'd take that over all the feats you listed combined.
Again, arrows disabling spellcasting is your personal house rule, not my problem.
Then maybe I misunderstood your rules. It looked like there were several ways to disable spellcasters. An arrow can take out the caster's mouth, preventing verbal casting. Armor can create an antimagic field. I think there were a couple other examples, which I forget.
Then, if you're pimping your nonhumanoid monsters with full wargear, well, the PCs would be in for a world of hurt even if it was "just" magic equipment.
Not full wargear. I'm pimping monsters with they normal total wealth, spent on pure metal items, and putting them up against PCs with full magic equipment. The monsters still win. If the monsters had regular magic items, they'd lose. You make this clear in your description -- you want these items to be more powerful than magic items. All I'm saying here is that you should consider making the items common due to their price (so you'll never have a party of PCs without them), or a higher price to make them less common. Otherwise, you'll have some pretty serious balance issues.
How exactly? Fighter/barbarian drinks potion of invisibility (which also gives it time to gulp down some extra buffs), gets near with a spiked chain and trip feats, warrior is screwed because a pure metal bow still provokes Aoos for attempting to fire in melee.
You're giving all the advantages to the fighter or barbarian. I don't think I'm going to convince you of this in my current tired state, so I'll stop this line of argument for now.