The ending/whole second ark is bad if I didn't miss something
I'm not really good at writing these so it's going to be a list. Feel free to point out my mistakes because I feel like this was such a stupid ending I must have missed something
Near is a Mary Sue. I've heard that in the Manga he actually does investigate the case further but in the anime he just pretty much correctly guesses that L is Kira and that mikami is X-Kira and that there is even a thing called X-Kira. It just felt too quick as opposed to L who actually had to work on cracking the case. Near just talks to himself a bit and is suddenly suspicious of Light. By having him top L without even trying as hard as him, it feels like he hasn't earned this victory and makes him look like a villain even (obviously Light is the bad force of this story, I will get to that on my next point, but Near having it so easy when it comes to uncovering the mystery makes me despise him)
Light dying the way he did is an awesome ending for him. He is a murderer with a god complex, and having him handed the fact that he is just a lame psychopath at the end of the day, is awesome. But it didn't feel earned. For the previous reason I mentioned, about Near, but also because of what actually took him down. The real mistake that made him fall is Mikami's, when he pulled the death note out of the bank. It's totally unrelated to Light's real weakness which is his arrogance, which is what the whole show built on.
The twist is told in a weird way man. We're told about Light's "perfect" plan against Near. It pretty much seals every hole Near could've gone through to catch Kira. Right after this is established we learn from the twist that the note was actually faked again by Near, because of Mikami's mistake. And that feels to me, at least, like the show just lied to me. The twist feels like an excuse.
I do have more problems with the whole second arc like Mello lowering the IQ of every single person within a 20 meter radius from him by 70, but this is less important. And I also would like to mention that the first arc is phenomenal.
Feel free to correct me on any mistakes I might have made about the show, and I'm sorry about my (I think) sloppy english.