Woah...34 pages of comments, all because of an 11-word rule in the Player's Handbook? That's wild. So let's summarize, for those who are just joining the thread, and might not have the fortitude to read through almost 700 comments.
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1. The rule being discussed is "Druids will not wear armor or use shields made of metal." (PHB, pg. 64)
2. Certain people in this thread do not like this rule, for a variety of reasons. The majority of these reasons are:
- They feel it's too restrictive
- They feel it's outdated
- They would have preferred it have game mechanics (penalties, etc.)
- They would have preferred it be phrased differently
3. Those who don't like it can be divided into two groups: those who house-rule it (I will call them the Rule Benders), and those who claim it isn't a rule at all (let's call them the Rule Deniers). Everyone else either likes the rule or doesn't have a strong opinion about it, and so they play it as-written (the Rule Purists.)
4. The Rule Benders have listed many reasons why they don't like the rule, and suggested different work-arounds. The majority of these are:
- Ignore it entirely and let druids wear whatever they like
- Let the player decide if it's a religious, ethical, or physical restriction, if any
- Allow non-metallic armor materials (both historical and fantastical)
- Swap the druid's armor proficiency for something else (Unarmored Defense ability, for example)
- Add mechanical penalties (loss of spellcasting, etc.) when wearing metal
- Minor variations and combinations of the above
5. The Rule Deniers have presented their own arguments, most of which are:
- It's not a rule because of the way its phrased (i.e., "will" vs. "can't")
- It's not a rule because it's different from other rules
- It's not a rule because it tampers with player agency
- It's not a rule because they don't want it to be a rule
- It's not a rule because it's actually something else (a taboo, an ethos, a philosophy, etc.)
6. The Rule Purists are struggling to understand how this even became an issue:
- It's very clearly a rule, and a simple one at that.
- It has always been "a druid thing" since the earliest editions
- The rule's impact on the game is minimal
For my part: I'm a Rule Bender that allows non-metallic armor materials. But I'm aligned with the Rule Purists and share their sentiments.