Having a big party doesn't mean having the strongest party in Wizardry. You can try with 4 or even 3 characters.
They will gaing exp. accordingly x2 or x2.5 times faster and become as much stronger in the same time.
I've had 3 characters and finished the game much easily than with 8.
But, as it was said, the most important is the interest you will have in play. So having many characters of different classes can make game more attractive.
Enjoy
