^--- What he is saying is essentially the point. Also, with this change, weapons that do not get the benefit of having imp crit or weapon focus, can get a LITTLE BIT of crit range play now, namely the unique/CEP weapons we've added.
Most people will probably keep using slashing weapons because they're accustomed to the power located within them and the versatility. This may encourage people to mess around, or use other things, and in general it'll make the field more balanced out.
ALSO, in base PnP, as I've stated, Keen Edge is also supposed to work on piercing weapons as well, with Weapon of Impact, being a spell for blunt weapons only, and I think that was added in 3.5.
For some reason in NWN they decided to just make keen edge work on slashing weapons. It also happens that slashing weapons can get 12-20 crit ranges, two of them, and the rapier can only achieve with this a weapon property of keen. No other weapon type we have on the server could get to this 'level'. High crit multiplier weapons can still be keened, greataxes, scythes, battle axes, dwarven war axes.
It is more than enough for it to be expanded to all weapon types.