All jokes aside here,
I think it hasn't any point in making a dbz forum, and yorus doesn't look really special compared to the rest out there, there must be zillions of dbz forums out there, to talk about what? dbz? everybody nearly seen every episode by now!
The games made about it? they are discussed here as well, more members too to discus it with, (and think about it, why would they register to your forum to talk about them if they can do it here as well, this IS a dbz themed forum).
Akira Toriyama's other work? well if you make a forum about that, about every work of his, not just dbz, maybe then you'll have something a bit more unique then all these dbz forums piled on eachother, in a land called "internet".