The Witness idea that it was all some sort of bet with Satan to prove Jehovah's sovereignty is rather unique to them.
Furthermore, I think your analogy is a little bit misleading- since it makes the potential fault a trivial one. Imagine instead that you choose to have kids, knowing that someday you might have to give your life for one of them. Let's pretend that you're very smart so you even know that you will one day have to give your life for your kid. But hey, you might still be willing to do it- if you could also see how great it would be to raise a child, you might be willing to pay that price.
Um, this isn't exactly to defend the ransom doctrine. Afterall, it sort of assumes a trinitarian view point (the notion of self-sacrifice is much more palatable then sending someone else to die). Also, it still seems a bit odd, I'll grant you that.
There's this concept of degrees of free will- and the question is: could God have created humankind with just as much freewill, but less propensity to sin- or is that a logical impossibility? And can God do the logically impossible or not?
Lots of interesting questions, keep looking for answers, and remember that if you find your answer to be that the whole thing is nonsense you should accept that result with the same relief you would accept it if someone could show you how it made sense the other way.