Possible Nocturne rework?

Hello guys. I'm just another league player who wanted to get all of your opinions on an idea I had. I started playing league a few years ago and for a while I had been looking for a champion that looked really cool and at the same time was really strong. while I was scrolling through the champions I came across Nocturne. I thought he looked so cool so I saved up my IP for him. He was the first champion I ever bought and I loved him! he was such a cool champion and he was fun to use! But as I played with him more and more (Especially in ranked) I noticed he just wasn't very strong. He can't do much in team fights and if he uses his ult to dive in he has no escapes unless he has flash, (which has a 300 second cooldown). I honestly think his abilities either need to be tweaked or changed (I would prefer they would be tweaked). I actually came up with some ideas for each of his abilities and wondered what some of you might think about them.

Umbra Blades I don't think his passive needs to change really it's already pretty strong and is good for lifesteal so this can stay as is.

Duskbringer I think this ability above all others could use some tweaks and I think I came up with some decent ones. So you know how when it leaves a dusk trail and Noc walks through that trail, he can move through enemy units? Well what if he could use that same ability through walls and with the dusk trail he can then move through the walls. This may sound OP but lets be honest, there are so many champs with crazy escapes that can go through walls and stuff. Like LIssandra and shaco. If Nocturne is gonna be an assassin he should at least have some escapes for when he ults someone. Also if someone uses flash through a wall and is leaving a dusk trail it would be cool if the trail continued to follow them through the was so noc can just go right through it ( that part might actually be op but its just an extra idea).

Shroud of Darkness I think this ability should also be a shield that shields him based on his AP just because his w doesn't help him much in teamfights. Noc really was meant only to take on champs 1v1, which is completely useless in a ranked match where most of the mid and late games are teamfights anyways.

Unspeakable Horror If his duskbringer wasn't changed then I think at least this ability should have more range. Just because it's really easy to get out of his e and once you do you can easily destroy nocturne.

Paranoia This ability should have an AOE when he makes impact with an enemy champion like either a slow or a fear. otherwise its a pretty good move but like I said earlier, it's very useless in teamfights. even if he gets a kill, he has no escapes. If he can at least have a better cc method that would make him a bit more useful in teamfights. plus I think the cooldown is a bit unnecessary. There are so many champs with OP ults that have such a short cooldown. Kennen's ult is one a good example of this. (Though I love kennen a lot too)

Well this is just what I think about Nocturne. I love him as a champion. He looks so cool especially with his eternum skin! and he is fun to jg with. I just think he needs to be worked on a little bit. Any thoughts?