While certain classes are a better fit for the Artifice Saga--in part because of story, and in part because of the races--all D&D classes will have a place. The intent is to preserve the campaign as a
fantasy, despite its sci-fi inspirational origin.
While particular sub-classes will be associated with particular cultures, all options will be available to all characters because of the melting-pot atmosphere of Tiresia. As all characters will begin at 1st level, and most sub-classes are chosen after that, there is plenty of time to be exposed to cultural archetypes other than one's own.