Didn't get on much this weekend, but it appears that most of the discussion is about dragon and paladon armor(?), so I'll come back to this.
Something done on a whim is arbitrary. Simply being personal preference is not. A preference is not a whim.
Example. If I'm at a supermarket and I decide on a moments notice to grab a bag of M&Ms, that's a personal whim and is arbitrary. However, if I like M&Ms and I decide that I am going to get one bag whenever I go to the store, then it's not arbitrary.
Can alway count on you to go to tge dictionary, and then focus like a laser on a narrow part of that. Here, you've turned arbitrary into "on a whim", which is true, but not the only meaning of arbitrary. If you're designing to personal preference vice an objective or systematic goal, that's also arbitrary. The proof of this pudding is that everyone has different standards of personal preference, meaning making a choice based on it for one person is arbitrary.
But, I don't need to argue definitional semantics. You seem to prefer "based on my personal preference" to "arbitrary", and that works for me. Just replace "arbitrary" for "based on Max's personal preference" in my posts and my points don't change.
When it comes to realism, I don't just decide to change anything on a whim. I keep the rule the same for quite a while while I assess what it is that I don't like about it, if it's enough to warrant a change, and in what way it will be changed if and when I do decide to change it.
Nothing I do with the game is arbitrary.
This sounds an awful lot like game design, Max. Which has been a long running point: the way we play and what we value in games is often not what we think it is. Here, you go on about how you do realism for the sake of realism, and you don't do game design because that implies considering multiple goals of play and balancing them, which can't be because realism for realism. But, right above, you show that it's only where a game system doesn't feel right to you that you start your realism pass, so that's personal preferemce, not realism driving. You then consider the change carefully, presumably weighing against ease of play and other objectives of play, before naking any changes. This is exactly what you've rejected!
You don't realism for realism's sake, you use realism where and as much as appropriate to achieve your play goal of immersion, the threshold of which is personal taste. You balance this against ither play goals, like ease of play, and ignore realism where it conflicts too much but still allows for immersion. This was the point.
And, non-existent-trap sprung, that's aces, man! That's how it should be. Recognizing this doean't make it wrong, or lesser, it just shows you more clearly where the potholes are so you can better play around them. You get so busy winning a battle that you lose sight of the war. Pyrrhus may have some advice for you.