I don't think you can win a championship without having five good starters. If you win, your point guard will probably be known as great. But, that also brings up the type of point guard. Must the point guard be a scorer? A lot of people consider Tiny Archibald as the best point guard ever, but I don't remember his titles...
You must have a "smart" point guard. A good distributor of the ball, solid fundamentally in defense and running the offense. Not necessarily a big scorer, but dependable in all fazes of the game. She doesn't have to be "great", but has to be solid.
