The "logic" of Superman's powers

I have some thoughts on how I feel that Superman's powers should work. In my opinion, his powers should be limited to invulnerability, super speed, super strength, flight, heat vision, x-ray vision, telescopic and microscopic vision, and super/freeze breath.

I'm not a fan of him being over the top intelligent, like he was in Earth One. But on the other hand, I like the versions of him where he can learn languages very quickly. I kind of find that logical, because if he's able to move that fast, his head has to be capable to see the stuff he has to move around. Ergo - his mind has to be able to prosess information insanely quick, but that doesn't make him a genius. 

I have a problem with how some stories show that his powers can be transferred to humans. It just doesn't make any sense. His body is made in a way that's capable of absorbing and storing great amounts of solar energy, and that energy results in those powers. So a human body, that can't store solar energy, shouldn't be able to contain those powers! There are no ways for a human body to fuel them. I think a power transfer makes a bit more sense with Parasite, because he actually absorbs the solar energy that Superman had stored, then runs out after a while. Parasite still wouldn't have the right kind of body to prosess the energy into powers, but meh. I'll let that slip. Can't make sense of everything.

Ignoring that, I feel that he should be able to get his powers back again fairly quickly if he loses them though. How is it that when he loses his powers in different incarnations (like in Smallville), he remains powerless? Stupid. His body remains the same, so he should be able to just absorb sunlight from scratch again.

Should kryptonite work on him when he's powerless? On first thought, I would like to say no. It depends on what kryptonite actually does though. Does it kind of pull all the energy he has stored out of his body in a way that hurts him? If that's the case, how could the rock kill him? Shouldn't it sap all his energy, and stop when there's no more solar energy left, and leave him mortal? If the rock keeps on pulling out all his energy until he dies, it should work on him when he's powerless from another source as well. I'd say kryptonite should be twice as lethal when he's powerless.