The point of all the class options is that their actual fanbase wants to see their favorite class implemented. I suppose you could argue that they would have more appeal to a general audience if they reduced the class bloat, but they would take a hit with their core audience. Whether this makes good business sense is hard to say... but I'd wager that the developers (or many of them) are part of the core "Pathfinder crazy" audience, since you would have to be to embark on a project like this.
Also worth noting, aiming for a general audience by no means guarantees that you will attract a general audience. There are a LOT of games out there, and trying to compete with them outside of your core competency is a good way to go broke.
