I think that you're 'aware' of paths and basically you need to make teams and what teams are good is a great start/advantage.
If there is 'an exact correct best path' I don't know it, and it would be extremely difficult to figure out. Personally, I'm not keen on the SLKR path. I think it's long and leaves you with 2 similar teams. In fact I think personally (and a lot of this would be to do with morale and fun) I'd work on at least 4 core very good teams. Then move onto your GL.
JKR/Jedi, Bounty Hunters, Geos and CLS rebels have all been bandied above. Getting BH to work properly...........will teach you a lot. They're very difficult to get right.