Tom Cashel said:
F'rinstance...what if players rolled 4D6 (drop lowest), or even 5D6 (drop lowest), to generate ONE prime requisite...then roll straight 3D6 five times and arrange all scores as the player desires? This would give PCs their "heroic" qualities, and the ability to freely choose class, while avoiding the inflation.
You'd still get the issue that Kid Charlemagne points out - you'll tend to get characters with scores all over the place. It seems to me that stats for something like average people are prety tightly clustered around the average. The 3d6 distribution does peak around the average, but not very strongly. So, you'll have your high stat, yes, but it'll tend to be coupled with stats that are absurdly low. I don't mind an occasional character like that, but having that be the typical result would tend to break my suspension of disbelief.
If you want to keep characters focused near "average human" for stats, but allow them to have an occasional high stat, use a low-end point buy.
In thinking about Grit, my mind went to the genre for which (as I understand it) the term was coined - Westerns. In your typicla Western, the main characters are notably superior to common folk. They are better fighters, wittier, higher force of personality, tougher, the works. But Clint Eastwood movies are still gritty. Why?
Grit is more about the situation and presentation. It's more about choices and consequeces. It's about going it alone, with little help. It's about being dusty and dirty,both physically and metaphorically. It's about a lot of things, but character stats doesn't seem to be one of them.