I see your point about Atris...but the game (if you do play LS) does not really make it clear what happens to Atris after her defeat to you. Sure she helps, but would she be willing to sit on a council again - I don't know...I almost think that a deeper character development for her would be to take a role where she does not lead - a role that gives her the opportunity to do the things that she started to hate herself for (i.e. not going to war), now that would be interesting (and a true convert)!
I think that one thing to remember about the jedi is that they lead by a council (the sith might have a dominant leader) and therefore Visas would not necessarily lead but at least sit on the council...
And as far as the "third path" order members go, I think it would be way to simple to say that it is just a new school of jedi or sith. But what might be appropriate to say is a new school of force sensitives that differ from the jedi/sith in the ways that have been discussed in this thread. But clearly open to any that have adopted this philosophy - force sensitive, jedi, sith - doesn't matter, what matters is their belief in how/why the force is there/should be used...I really like Distorted's mantra to describe what this "third path" is about...
In chaos there is balance
In balance there is the order of all things
In the order of things one can free themself
In freedom there is choice
In choice there is responsibility
In responsibility there is the force
I think that this sums up what this "third path" should be about - ambigous yes, but at the same time understandable.
Two more quick things...
1. We know that the republic is around for at least another 4000 years...
2. Two GOTO states in game that in order for the Republic to survive someone with force sensitivity would need to fill the power vaccuum - jedi, sith, new order? - doesn't matter as long as someone does it.