Nocturne being classified as a Tank Assassin rather than an Assassin Fighter.

So ive played nocturne ever since i pretty much started playing league and ik im not the best but i just want to talk about how in the current meta he doesnt really seem to fit the title of and assassin fighter. Everything I say is just my opinion and i just want it out there. I just feel like Nocturne should be classified as an assassin tank kind of champ. When you look at recommended builds it shows certain items that give u alot of health, armor, and mr. and it works well with him to a point. Ik hes a single target kind of champ and by that i mean he targets one person and mainly one person only when ulting. HIs passive well heals him to a point depending on base lifesteal and its aoe. His Q shows it as more of an aoe skillshot which means it could hit more than one person, His W is a spell shield and it only takes one hit to get rid of it, I think it should be something like morgana's spell shield because he puts himself out there and gets pummeled on and doesnt really get much of a chance to get away or defend himself. His E is a single target spell but it could be somethign close to like warwicks new fear as an aoe cast so that way whenever he goes in on a group of ppl he has a split second to single someone out and get them, like an assassin. His R is also a single target, I like the concept of it and how it works. I just wish there was a way to make it like scarier or more useful in different ways, like if he was to ult on someone he could fear them or cast like a blind on the surrounding champs on the person he targets so he can single them out to a point. Kind of like how his ult works when activated the first time it cast a shadow on the map and gives nobody vision of the minimap or of their area. But thats just my thoughts on how he should feel more like a tank that works as a group then singling ppl out. Thank you :D