Hmm, it is surprising only up-front. After all, one can look at what others do to find the good things more easily, and also to see what everyone has and thus can avoid accidently duplicating it if it is nothing essential.
In this particular case, the more I think about it, the WoW example reinforces it: if even a game like WoW sees the need for such a limit, while they obviously usually would not care from the RP aspect, and marketroids would suggest having no limits, then there likely are other, actually important reasons to do so. I.e., everything that, in a commercial game, works against what marketroids would suggest, must have real reasons that are likely to appear in PS as well.
Anyway, Xordan has already stated that the system is only a preliminary kludge to have
some system, and that it will be replaced by something better and more adapted to PS eventually, like the dwarven model for the waybread.

Edit: speaking of models... I need to delete one of the weapon models to see people wield dwarves!
