Yes, of course every Superman/Clark makes mistakes, sometime becuse he is "human" too, sometimes because some idiots had written it that way.
The clone Thing is something I wondere about too. It seems so weird for Clark to just let him die and doing nothing against it, especially after he started so see him as a sort of brother.
The "NoS"-affair seems just terribly written and totally out-of-characer, though one could say that we're talking about a younger Clark here, who hasn't all of his future knowledge etc. but it still seems odd.
And soullmates... well, this is a chapter for itself and I'm still not sure what to think about this concept..
But no one said L&C Clark is perfect, too. I think every Clark has some Thing he could learn from other Versions of himself.
