With the introduction of many different classes, the original meaning of the SIWDCC order was lost, which is why WotC have adopted a Physical/Mental divide, listing abilities as: Strength, Constitution, Dexterity, Intelligence, Wisdom and Charisma.
The modern order doesn't bother me; it seems to make sense, and I like the Physical/Mental division. Here is a great post about the subject, by the way.
There is at least one interesting (and probably accidental) feature of SIWDCC: when you think of most common archetypes, each pair of abilities can be viewed as "opposites" in a way.
Here is what I mean:
Strength x Intelligence: the dumb brute versus the weak wizard or scholar; Fighter versus Magic-user.
Wisdom x Dexterity: careful consideration and patience versus quick action; Cleric versus Thief.
Constitution x Charisma: the rugged, stoic type versus the sweet-talking singer or swindler. Dwarf versus Elf, or Ranger versus Bard.
This is mainly a curiosity; some D&D archetypes and classes will need "opposite" attributes (monks, assassins, etc), but it can become useful when generating NPCs or even PCs if you want results that might a little more sense than 3d6 in order (and yes, I get it, it might be cool to think of a justification for seemingly disparate abilities),
For example, let us assume you're using 3d6 in order and want "balanced" characters (i.e, not straight 18s or "hopeless" characters).
Try this: roll 3d6, write down the result, subtract this result from 21, and write down the new result. You now have two results that add to 21; for example, 15 and 6, 18 and 3, 7 and 14, etc.
Do this two more times, and you have three pairs of results (for example: 15 and 6, 18 and 3, 7 and 14).
(If you are using the "4d6 drop lowest" method you can make the sum of each pair equal to 24 or 25; see the table below).
If you already know the type of character you want, distribute the results accordingly - the original pairs should be kept.
For example, if we are creating a Wizard, we can use: Strength 3, Intelligence 18, Wisdom 15, Dexterity 6, Constitution 7, and Charisma 14. This is an old, wise wizard; a quick-thinking, smart but inattentive wizard (another common archetype) with the same numbers could have Dexterity 15 and Wisdom 6 instead.
A big, dumb Fighter, like Gregor Clegane from A Game of Thrones, would have Strength 18, Intelligence 3, Wisdom 7, Dexterity 14, Constitution 15, and Charisma 6.
If you don't know the type of character you want, use the original order (i.e., just fill the character sheet in order): Strength 15, Intelligence 6, Wisdom 18 , Dexterity 3, Constitution 7, and Charisma 14. This looks like some kind of stoic cleric (or paladin) to me; maybe an old veteran, a natural leader, still a good fighter although somewhat fragile and slowed down by age.
Let us try some other examples? I rolled these as I was writing, with no re-rolls, I promise:
- First I got 9, 12, 9, 12, 10, 11... yeah, a bit boring. Maybe I should do something to avoid such results. In any case, it clearly looks like a Thief (Strength 9, Intelligence 12, Wisdom 9, Dexterity 12, Constitution 10, and Charisma 11).
- Strength 15, Intelligence 6, Wisdom 12, Dexterity 9, Constitution 11, and Charisma 10. Your typical Fighter: strong, a bit slow, but with enough courage and common sense. Maybe a soldier or tough knight.
- Strength 11, Intelligence 10, Wisdom 14, Dexterity 7, Constitution 14, and Charisma 7. An average Cleric, hardy and strong-willed.
Most iconic classes AND races in D&D I can think off would fit in this Yin-Yang pattern, but a few exceptions can be made. The Monk (or Mystic), which requires Wisdom and Dexterity, seems to be the main problem (the Ranger in 5e is similar - although I would argue the archetypal Ranger would need Constitution or even Strength before Dexterity, if you think of Aragorn). There are also, of course, plenty of classes that rely on multiple abilities; a Paladin or Warlord might need both Charisma and Constitution, but also Strength, and probably some Wisdom or Intelligence (come to think of it, the Ranger and Monk could use some Strength and Constitution too...).
There are also some non-iconic "special classes" that would break the mold. The Muscle Wizard comes to mind. Some kind of super-model/celebrity class could be built around Constitution and Charisma.
For all those classes, some special exceptions would have to be made to make them "optimal" or even viable; one option is on the second table, below.
|Source. Or maybe here?|
If you don't like subtracting, use this to find the value of the second ability in each pair:
What is the point?
This method is good for creating fast, random, balanced, archetypal characters. If you want more creative results, less randomness, more customization, and so on, many traditional methods will do just fine.
UPDATE: reading the AD&D PHB again, there are some additional reasons to believe this is a deliberate pattern: a low Strength character can only be a Magic-User, while a low Intelligence character can only be a Fighter; a low Dexterity character can only be a Cleric, and for low Wisdom, a thief. On the other hand, special classes such as the Assassin, Illusionist and Monk break the mold.