feuer_faust
Explorer
In my opinion, it's not so much that humans are weaker than the other races, but that the other races are more desirable than in third edition. No more stat penalties and some shiney new core races means humans will be put off to the side more often in favor of the demi-humans. This is the reverse of the trend I saw in my local area, were human characters were amazingly prevalent due to their ease of use (so to speak).