If a character rolls a "1" on a to hit roll with a bronze weapon, the blade bends, and needs to be beaten back into shape before being able to be used again.
I would not recommend such a rule. Loosing a weapon for every 20 attacks you make is neither fun nor realistic IMO. For a high level fighter weapons will have a lifetime of about 30 seconds before he has broken them.
As for more primitive magic. Id say
1. loose the wizard (they are the most advanced of spellcasters)
2. keep the cleric but reduce and tailor the spell list to each god (aiming for about 10-15 spells per spell level). This is to reflect the relative newness of the organised religions. They havent had time to research/share many spells yet.
3. keep the sorcerer and allow them spells from the standard spell list and the druid spell list. Remove all spells dealing with items/technology (like arcane lock, locate object etc.) and those dealing with other planes (summon monster, teleport, rope trick etc.). Drop the familiar and up the skill points to 4/level and use the combined skill list of the sorcerer and the druid class. This is the adept on steroids and reflects the natural/primitive spellcaster.