It pleases me that you've put effort into expressing your opinion. Did it really require a childish taunt for you to do so?
As I've said, the second half of the story is weaker than the first. Death Note fans agree. Madhouse agree. I'm not even going to suggest that the first and second halves of the story match-up in terms of quality. But 3/10, for episodes with top direction, music placement and plenty of manga fixing? The number doesn't fit. If you want to see a proper 3/10 series, watch Doki Doki School Days. Or, if you want to see a studio **** up the source material and put no effort into the art/animation side, watch Shippuuden.
In the second half of the story, the author lost his touch for a lengthy period, and even when he bounced back with Mikami's introduction he still created plot holes in order to reach the conclusion. There's also the argument that the second half of the story wasn't required - that the story should've ended with L.
However, although I'm fully aware of the shortcomings of the last half of the story, I still liked it. Why? Because I understood what the author attempted to do. He didn't want the main character to die without getting a major victory first - he felt that would've been a pathetic way for such an intelligent character to go out. He did want him to lose, but not straight away. So, in order to pull this off, he had L die and, in his place, created two new rivals for Light - one like L (Near) and one more like Light (Mello). L alone couldn't beat Light, so he made it 2 vs 1 to be fair.
It wasn't the idea of two new rivals coming after L that was bad - it was the execution. At first it went well, with Near leading the Americans and Mello leading the mafia, but it started to go wrong after Light's dad got killed by Mello. After that, Mello had no role to play in the story - it was all Light vs. Near. The author didn't know what to do with Mello at this point. And, sadly, what he ended up doing was making Mello do something he'd never do in order for Near to win: sacrifice himself. His character was ruined there and then. If Mello had ever been shown to be the kind of guy who'd throw away his own life for the greater good, the twist would've worked, but he'd never been shown in that light until his demise.
I don't think Mello's character change damaged Death Note a great deal, though. He should've been removed from the picture earlier, and the author should've come up with a different way for Light to lose, but no lasting damage was done... providing you can ignore what happened to a character who was wasted. I'm in the camp that believes the poor job the author did with Mello was made up for by the warehouse sequence at the end.
As a whole, the second half of the manga was less than impressive. There was too much pointless talking, too many needless plot twists and not enough of Light doing his thing. But the anime is different. 50+ chapters were sped through in 11.5 episodes, with all of the needless content cut. What resulted was a fast and thrilling ride, with all the good of the second half of the manga and a limited amount of the bad. If I overlook the few plot holes, Near being an L clone and Madhouse ******* up the ending, I see little reason for me to not give the series as a whole 10/10, or close to it.
Unless you read the manga, you just won't get how good of a job Madhouse did... the ending **** up aside. They put effort into even the smallest of things, ranging from Light eating crisps to Light getting out of a car door (There was even a new, only played once track that accompanied that scene). And, as has been mentioned on numerous occasions, they cared enough about the source material to want to fix problems. In an age where anime studios are known for not spending money and screwing up perfectly good stories, you have to give them credit for doing the best they could. Does a 5/10 score reflect this, or the quality of the first half (2/3rds in the anime) of the story, which you said you liked? Nope - it'd make a person think of Studio Pierrot's adaptation of another Bleach or Naruto.
Having read your post, it's clear you haven't read the manga and, in some cases, just didn't understand what you'd seen.
L vs. Light, a conflicting clash of beliefs? No. L and Light are very similar characters. Both are the type who'd discard others if it meant winning. Neither of them valued life very highly. That's why, during the Yotsuba business, L argued with the other team members, who refused to accept the idea of letting people die in order to catch Kira.
L thought Light was childish, but he himself admitted to being childish. He also said that's why he could predict Kira's moves - because of their similar way of thinking.
Light became more evil as the story progressed? No. If you want to think of him as "evil", he was evil right from the start. He never cared about his family, he never had any true friends. His brilliance and lack of heart isolated him long before he found a Death Note. All the Death Note ever did was allow him to be true to himself; allow him to break away from the chains of society.
You go on to say he's hard to relate with, yet many people can relate with him. Lots of people put on fronts around others, acting kind when they don't really give a ****. Lots of people think of the world as a mess, full of disgusting people. Lots of people would kill others if they knew they'd get away with it. You may not agree with Light's actions but, in my opinion, there's a bit of Light in everybody hiding somewhere under the surface, masked by a fake smile.
I also fail to comprehend why you believe Light's actions on his fathers death bed somehow contradicted his earlier actions. Was Light ever shown to think of his father as anything other than a pawn? Even earlier on, after the tennis match, Light felt he had to act like the good son in front of L. To be frank, you're talking out of your arse.
Moving onto your 'point' about Ryuk, once again you failed to grasp something: Ryuk wasn't shown much in the second half because of the surprise role he played at the end. He didn't want Ryuk to be at the front of the readers mind. I'll cut you some slack here because, due to the Madhouse ending, it looked like Ryuk took pity on Light. In the manga... well, I don't want to spoil it but I'll just say that the author was saving Ryuk for the finale.
Switching again, this time to L, I chuckled at your comment regarded L's "special ability to hear bells". I sense much density. First of all, you have no way of knowing this but the bell thing was filler. Secondly, the meaning behind L hearing bells was obviously that he knew his end was fast approaching. If you didn't get that when you watched the scene, you most certainly should've after L died almost straight after.
...I'd best wrap this up. Most likely, you'll be too lazy to read this in any event. In summary, I'm well aware of the flaws of the second half of the story, but I feel it saves itself towards the end - from Mikami's introduction onwards - and I also believe that Madhouse did such a good job that it remained close to being as thrilling as the first half of the story in the anime.
This will be my last post because I'm trying not to use the net - typing lengthy messages does not help. You should feel proud that I've gone to the trouble of typing this message. If you feel like rewarding me and need to get the stains of '5/10' anime off your hands, send me your copies of volumes four and five. I'll even cover postage.