A small buff idea for Nocturne

As someone who has always loved the champion even if I don't play him that much I have an idea for a small Nocturne buff. I believe I saw this being suggested or worked on a long time ago, but I haven't seen it since. The change would be for his ultimate to only go on half cooldown if the dash portion of it is not used. The vision denial can be used for great denial of ultimates like Shen and Twisted Fate, but a lot of times it isn't worth it to lose the dash due to the long cooldown and it being his main ganking tool. Allowing players to play around with the vision denial mechanic I think would be a great small buff to Nocturne and really fit his theme as a champion.