Since we will be able to specialise, it only makes sense, that a guy who started as melee should be better in it, than someone who started specialising into archery, however I think it should be possible to make a build that is as good in melee as every other melee warrior at the expense of more grind.
Also, I think that balancing classes, should be about sustainability. For example, it will be cheaper to play a guy with a sword than a guy with a sword and a bow and a bag of arrows, because a sword won't break as often as arrows or strings for the bow or the actual bow.