DuTwan:

the force was a mystical energy that could be wielded by anyone with the right training, the force was stronger with some families.

Well that sort of contradicts the point you're making.

There's a simple question: Why is the Force stronger with some families, as Return of the Jedi establishes?

Answer given in the prequels: It's genetic.

Again, I don't like the writing in the PT at all, but I don't see why a genetic quality is such a bad thing with regards to Force sensitivity. I think Lucas wrote it very badly, but perhaps that, coupled with all the genetic manipulation/cloning stuff going on was his way of making the PT relevant in some way.