Isn't the proficiency bonus the weapon attack bonus? Attacks with non-proficient weapons are straight ability rolls right?
I was talking comparatively, as should really have been obvious.I meant objectively, as should really have been obvious. If you're going to talk comparitively, then it makes no difference whether proficiency gives a bonus or merely negates a penalty. Hell, it would make no difference if non-proficient characters got a +20 bonus and proficient ones a +24 bonus - the DCs on tests would need to be scaled accordingly, with the net result that the raw probabilities of success would be the same.
Yet realistically, skills are a combination of raw ability and training. You can train all you want to dig a ditch, but someone physically more powerful than yourself is still going to do better with less training.It would do exactly what it does with skills - replacing the bonuses means that you replace the effect of raw aptitude with the effects of training.