He wants to see within this man a true desire to be cured; some affirmation of a desire to rise up and walk in a world which is full [of] uncertainty, perhaps greater uncertainty than he feels at the poolside.
This is the opposite to what many use Christianity for. They use it- and I suppose this is why there have been so many religions in the world- to reduce uncertainty. We don't know why x,y, or z happens, so lets create a myth about it. It doesn't matter if that myth is straight up pagan, comes in Christian clothing, or is created using scientific language. Conveying uncertainty to these people, at the very least, confuses them, perhaps like the man at the pool was confused.
He alone sees all that we do and earnestly desires us to be perfected.
Ah, to be perfected. You know, you'll find this desire in a gym before you'll find it in a church nowadays. On one level, this is an existential necessity- if you aren't struggling to improve, you are in serious trouble. It is a simple biological necessity- stay on that couch, watch crap T.V., and eat processed food- and you will suffer consequences. So, the need to perfect yourself is baked into to our biology. Meanwhile, we can see quite clearly, especially as we try to improve, that perfection is impossible under our own power.
Anyway, I think healing and being perfected are related. It seems extremely unlikely to me that someone would be healed of diabetes, for instance, so that they could go back to eating cakes and donuts with abandon. Diabetes is bad, but it is also a response to injury. You've got to stop damaging yourself, or else even if God did heal you, you'd just get sick again.