[Langy]

ATTRIBUTES
I like p. B14 well enough, but I might add some more categories:
6 or less Crippling (literally -- you can't live a normal life)
7 Poor (you can life a normal life, with care, but never be an adventurer)
8-9 Below Average (low side of able-bodied, probably the lowest an adventurer should ever have)
10 Average (most scores for most people)
11-12 Above Average (high side of able-bodied, probably a good average for adventurers)
13-14 Exceptional (highest you'll likely meet on the street, above average for adventurers)
15-16 Amazing (highest you'll likely see or hear about, strongly defines an adventurer)
17-18 Legendary (historical "bests" and remarkable fictional heroes)
19-20 Mythic (astounding even among great heroes in fiction and folklore)
21 or more Superhuman (off-limits to humans, barely suitable for great heroes, okay for deities)

I like this a lot. It makes the 17-18 group have only a few people in the planet (which sounds a hell of a lot more reasonable than there being 6-7 people with stat-20 around today, which is so high they're experts at almost anything they even attempt, much less actually study for), and it describes things rather well.

In an earlier, somewhat contentious thread, it is demonstrated that the values given on p. B14 establish a standard deviation of about 3 attribute points

That can't possibly be right. Look at the effects of what stat-16 or higher gives you. That's only two 'standard deviations' by your method - two standard deviations is approximately 95% of a normal population, so 2.5% of the population would have better than a 16 in any stat. That's crazy talk right there.

Besides, saying 'most people have between 7-13' just means the standard deviation is probably something less than three. Three is approximately the maximum, not the actual value. The standard deviation could be 1, leaving 9-11 as 65%-ish, 8-12 95%, 7-13 99.5%, etc., and those are still 'the majority', because 99.5% is still greater than 50%.