JCD7 said:
This may not jibe with most people, but what bothers me about ASF is the lack of explanation behind it.
I don't think there have been a lack of explanations. If anything, I think there have been too many of them, it's just that no one explanation covers all the problems people have come up with. They clearly just started with a few sacred cows like "arcane magic and armor don't mix" and then tried to rationalize it as well as they could. It makes for a balanced game system, but doesn't really do much for the immersion factor.
I've heard "it interferes with gestures", which explains why spells without a somatic component don't suffer. But, it doesn't explain about Clerics.
I've heard "they're not trained", which doesn't explain why multiclassing or armor Feats don't make up for this.
I've heard "it's an energy thing, inherent to the magic type", which doesn't explain the PrCs (and now in 3.5E, the core Bard) that can cast arcane spells in light armor without penalty.
No matter how you rationalize it, though, it's still a screwy system. Remember, randomness favors the bad guy, and ASF is all about randomness. Let's say the Wizard is wearing Celestial Chainmail (15% ASF). He has one critical spell memorized, and tries to cast it. If he succeeds, and he usually will, then the armor didn't penalize at all. If he fails, we're looking at a possible TPK; will he look at the situation and say "Well, it was my fault"? No, he'll say that the dice screwed him over.
Random failures are bad. Consistent penalties are good. It'd be so much simpler if they removed ASF altogether and rolled it into the other stats, making it a constant reduction the Wizard could plan for.
For example, make the Armor Check Penalty of the armor subtract from both your caster level (for the purposes of spell effects, SR, dispel checks, etc.) and your Concentration checks. Maybe Save DC, too. If there's no ACP, there's no reduction in power. This'd really explain why Elven Chain is so good for casters.
Of course, right now light armor is superior to heavy armor in general, even for the Fighter-types, so really high ASF isn't an issue.