Well, in my hopinion one character per player would make the game more "MMO". There should be the possibility to make a crafter with decent combat skills, at least for fighting weaker NPCs alone, but still unable to make any resistamce to Unity and so on (Jhans should already be a problem).
Having one char per player would basically make player's social skills very important: as you said, crafters will have the economy power, and fighters can offer their protection. Gangs also will have more sense. There will be crafters, hunters and fighters according to everyone's favourite way to play the game.