He does upgrade his weapon so that it can shoot darts, knives and later, who knows what.
He can also merge items for use and he can use items in battle, i.e. the lightning rod is an Enery Blast of a significant enough level to compensate where he lacks in sword skills early in the game, you just have to pay attention to his stamina when he uses it.
I have a game of nothing but basic characters and one is a gadgeteer, however I gave it up to play with the game I had going first, an all elite team except for the mage who were way ahead of the new party with the gadgeteer so I can't be of any more help to you in your decision to keep him or not, but I have found some gadgets throughout the Elite game that have me intrigued to get back to the basic party.
I can't see Wizardry creating a useless character.
Fellow member, Analander, is working on a list of items the gadgeteer can make and use...check the link in his signature to get to the site.
