I think the "balancing force" thing works out a bit like this:
The Jedi have stamped the Sith out, long long time ago, except for a tiny secret cult that keeps the hatred alive, waiting for a time when they can make their move.
With no enemy of their own level to fight, the Jedi become peacekeepers and police for the Republic. On the philosophical level, they turn inwards. Since giving in to hatred, envy and similar dark emotions leads one to the dark side, they try to eliminate those emotions.
And while they are at that, they get antsy about all other strong emotions. If hatred leads to Dark Side, what about jealousy? Or despair? Or fear for one's loved ones? They don't want to take the risk.
So the Jedi instigate a new recruitment program. Take them in early, separated from their parents, and raise them as cool, calm people with no emotional attachments to anything except the Order and, possibly, the Republic.
This doesn't work. The Order starts to ossify. (I think this is a good explanation why the Jedi never saved Shmi afterwards; they didn't think it very important. Maybe they made some inquiries, found out that she was sold to a decent man, and thought that wrapped it up nicely. No Mom to disturb young Anakin, and so on.)
The "balancing Force" thing by Anakin means that he should bring emotions and life back to the Jedi. Unfortunately, the fossilization of the Order has gotten too far, and Palpatine's Sith influence is growing too fast, and wham! Anakin slides to the Dark Side, butchering the majority of the Jedi. (I believe that Obi-Wan and Yoda were not the only survivors of the purges; just the only Jedi Masters who made it. There are probably padwans and even full Jedi Knights out there, hiding from the Imperium.)
So the job falls on Luke's shoulders, and the kid seems to manage it. He believes in good in people, he helps his friends even if it puts him in risk, he wants the truth (as opposed to Obi-Wan and Yoda, who both manipulate him; for good ends, yes, but manipulate never the less), and he wants to save his father. And he does it.
When Luke is restarting the Jedi, I'm sure they will be better balanced people.