I know this is the rules forum and not the opinion's forum, but my gut reaction is "the only special thing about that ruling is..." nevermind, it's not pretty.
Ok, let's assume all categories of weapons are basically equal, so generic Fighter A pics martial weapon A because he likes the concept, not because it's I33+. A rapier is 1d6, 18-20/x2 which is pretty close to a longsword at 1d8, 19-20/x2, and so forth. Simple weapons tend to be a wee bit less viable, and exotic weapons tend to be a wee bit more powerful.
So if all weapons are basically equal, then all critical improvements are basically equal. Changing an 18-20/2 to a 15-20/x2 is about the same as a 19-20/x2 becoming a 17-20/x2, since their base damages are different. And furthermore, increasing an 18-20/x2 to a 15-20/x2 is also the same jump blah blah blah.
According to Andy's statement, he's tired of the 12-20 crit ranges. That's really only feasible for an 18-20 weapon, Keened, with improved critical. By the base rules, we're only talking about a guy wielding a kukri, scimitar, falchion or rapier, who has a +8 or better BAB and spent a feat and either uses a Keen spell, the keen weapon enhancement or a scabbard of keenness. That's pretty rare. (Two PrC's that I can think of add crit ranges, so that's even more rare and they're not core rules anyway.)
Is this such a problem? These PCs are already paying a lot of opportunity costs to do marginally more damage. Now they'll take that feat and plow it into specialization, or power attack, or weapon focus, and the saved loot cost for the magic item and invest it in a higher bonus to hit and damage. Wowzers, nothing's changed except a flavorful mechanic.
This so far has won the "dumbest rules change for 3.5 award" for me (barely eking out the "two-handed power attack is I33+" rule).
Greg