Firstly, I hafta give you an applaud merely for your name and dedication to hide <3
Secondly, you made some very interesting points!
i mean no matter who it is they deserve a 2nd chance or perhaps even a 3rd and a 4th etc. Its just not right. But heck its what the anime is about and i love it.
Speaking from experience, there is a point where, when given another chance, then another, and another, it becomes obvious that you're being taken for granted, and it's jsut foolish to give so many chances. The saying goes "fool me once, shame on you, fool me twice, shame on me"
Some people you just cannot change, though i understand where you're coming from. I think it's best to say, rather than saying that you would give them another chance, the death penalty should be altogether removed, so payment for previous behaviour can be given, whereas, with death upon conviction, it doesn't leave a chance for any being who has been placed with such a charge, to redeem himself, or to be found innocent, when he was proven guilty. It's an entirely split argument, that appears to have no right, nor wrong answer logically, seeing as we have ideas such as "treat others how you would like to be treated" and "an eye for an eye, tooth for a tooth", but morally, counterbalances, in our human nature, step in and explain that "if it was an eye for a eye, we'd all be blind" and such. (gosh, I'm waffling again...¬¬ think I'm actually going to have to write an essay for this at some point)
Besides. if shinigamis existed whos to know what else exists. Also this opens the possibility of "L" having supernaternal aid / abilities himself. The realm of DN is pretty similar to ours therefore its not normal for a detective to deduce a murderer of having supernatural abilities in which only a name and a face is needed to kill.
I think, when it all comes down to it, there is an ability to think outside of the realms of possibility that we know we are confined to, when there is no other possible explanation. There is no humaly possible way to kill as many people as Light does, overseas, at the same time as other, with a heart attack, something which, while not untriggerable, is hard to cause in perfectly healthy beings.
There has been some discussion of whether L has a mental disorder, specifically Asperger's syndrome, so it may be that that helps him to deduce the supernatural part of the killings.
And now, I'm going to go back to my coursework before I annoy people...