One change that I noticed during the course of the 3e, and continuing into 4e was the expectation that a fighter would have an 18 strength, a wizard would have an 18 intelligence, etc., as starting characters. It's not an absolute, by any means, but it certainly doesn't seem to be remarkable to see multiple 18s in one party. I know my group has seen a bit of escalation, in this area, over the years. In AD&D, we typically felt pretty good about a 16 in the prime requisite stat, saw a number of 15s, and either rejoiced at our luck (if using dice) or made sacrifices (point buy) when we had an 18.