This seems to be the opposite of what the OP wants. The idea is that iron is not a good conduit for magic.
He also mention that iron was banned, which would need a reason why.
You can also add in that cast spells while holding iron has a penalty (spell failure, DC lowered, uses higher spell level than normal)
Giving Iron clear advantages does a few things:
- PC want to use it, but it would get them in trouble
- PC see enemy has Iron, and realize the fight will be A LOT harder
- Quests to hunt down Iron users or suppliers
With a near utopia, you need to find conflict some where, so Iron would be 1 source of that
I'd consider it a "Near Utopia" not a "Perfect Utopia", because that would be lacking the Free Will.
A Farmers Guild would be in control of all farms. Guilds allow for political intrigue and investigation quests. Food in general would be unlimited, so the Guild is used to artificially enforced certain item limits.
Farmers would have to be guild members and get licenses for crops / animals, with some crops only have a few licences allowed ie: grapes, strawberries, coconut, lime beans.
Normally farmers farmers would never have enough time to do what's needed. These Guild Farmers have enough magic available that they have lots of free time, hence the tight regulations. Lycanthropes would the biggest threat to the Farmers.
Construction would use a good chunk of the lower class labor. Not for expansion, but for the nobles to tear down houses and build new ones every few years. Resources would not be an issue, just the labor to tear down and rebuild.
Actual magical weapons could be very rare or even not exist. This would give Lycanthropes a greater threat with the limited supply of silver.