I have had a radical ability score idea for a while (I suggested it for 4E back in the day when we didn't know much about it), which I would like to share. It is not really appropriate for the Pathfinder RPG, as there would be compatibility issues, but this is the new rules suggestion forum and despite its lack of relevance to the PFRPG, I don't know where else to put it so I decided to post it herein.
The normal population would not have its ability scores modeled by 3d6, but by 4d4. This would give a range of ability scores from 4-16 (rather than from 3-18) and the average (mean) score would be precisely 10 (rather than 10.5). The ability scores would be more tigtly clustered around 10, since 4d4 has a lower standard deviation than 3d6 and the probability of the most extreme scores would be lower.
An ability score of 10 would provide no bonuses or penalties, but each point an ability score was higher than 10 would provide a +1 bonus to the relevant rolls, whereas each point an ability score was lower would provide a -1 penalty. Why not just use bonuses and penalties then? Because it is counterintuitive and sounds wrong - imagine somebody saying he has an intelligence of -2...
Of course, racial boni would tend to be +1 (or -1) rather than +/-2.
I think the numbers for the 4d4 distribution come out neater than for the 3d6 distribution.
Of course, PCs could use different methods to generate their scores, for example, 3d4+4 or 2d6+4, to give them a higher probability of getting good scores.
What do you think? (Not as a Pathfinder RPG idea, but as a more general, theoretical idea...)