[Turin]

well I gave the orokestes the forge bonus, because it says n his flavour text that he had a long search for knowledge and learned a lot of magic, so more efficient item forging fits.

But the main reason is that the forgebonus makes him an interesting hero. Base game he is just another mystic with priest levels. The priest levels are mostly useless and lots of one path magic makes him most useful as a researcher. So he is just plain boring.
With the forge bonus he will play an important part in your game, because you will want to figure out how to best equip him with boosters to forge your important items and he will generally play an important role. So he suddenly becomes interesting.