I hope Nocturne is taken in a similar direction to Fiddlesticks.
So after seeing the awesome concepts Rioters have made for Fiddlesticks it makes me hopeful that Nocture will follow the same "Eldritch horror" path instead of just being a cool shadow with blades. The third concept in particular is what made me think of this, I think Nocturne could work as some sort of shapeless shadow with many eyes that takes form as he needs to. He is also this creature that delves into the deepest fears of each person he tortures so he could have a ton of neat interactions with each faction and some specific champions, like if he fears a Demacian he says something like "Demacia will fall" and so on. As for his abilities they said they wanted to keep his ultimate which I agree with, but I also think some sort of ability that makes him untargettable while doing damage to the enemy would be pretty cool, sort of like a mini-DOT Umbral Tresspass, could be a fine replacement for his spellshield and would work really well with Duskblade, an item that thematically fits the champion well. Some sort of isolation mechanic either like Mordekaiser or Kha'Zix' would also fit him but maybe his R already does that well enough, speaking of which what his ult also does well is making players play really safe in fear of getting caught by him and giving them a feel of hopelessness when their screen suddenlygoes red after they make a misplay and decide to wander off alone so I hope he doesn't lose that identity, but like I said as long as his ult stays that shall remain the case.