On a national level, and to a lesser extent on a state level, having two primary parties and some smaller fringe parties is really the only feasible way our system can work.
Not only is it doubtfull you can create more than two viable parties, its damn near impossible. Far to many people will vote against their own intrests if they have reason to believe that if they don't something even worse could happen, leaving in its wake a two party system.
In fact, the same reason we have a two party system is a big part of the problem with our current system. Just imagine how easy it would be to promote expanding an uninformed electorate under the guise of helping them, then vilifying the other party to make themselves look like the lesser of two evils.