Design patterns to further define marksmen as a class moving forward
Let me start off by saying that I like the current state of League and I'm an ADC main. I don't think ADCs are particularly overpowered and the game in general strikes a good balance between all classes at the moment. I also don't want to change anything about any of the current ADC champions, I think they're fine how they are. My only intention with this post is to present some ideas that I think would be cool on a marksman if a new one were to be developed. I should also mention I have a bias toward designs that have strong strengths and weaknesses vs. generalists that are decent at everything and only slightly better at one.
##1. A marksman with a minimum attack range I think it would be interesting to explore a champion that can't auto attack in close quarters. This would make sense on a champion with a long rifle. As a tradeoff they would have an increased range (maybe 700-750) and perhaps better than average damage or attack speed for a marksman. Maybe a small dash with a root (like caitlyn's net) on a hefty cooldown as well so they can get out of that minimum range and have more counterplay against melees.
##2. A marksman with charge-up accuracy This would be a marksman that needs to take aim and focus every auto attack. So you would right click an enemy and your champion would stop to focus while a meter charges up. If you move or attack another target (or the meter reaches 100%), the auto attack fires and hits with the accuracy the meter got to. The charge time would increase proportional to the distance the target is from you, being almost instantaneous when shooting directly in front you. To take this even further it would be interesting if this champion also had a global range. So if you attacked a visible enemy top laner from bot lane, maybe the charge time would take 10 seconds to reach 100%.
##3. A marksman with fixed, less than perfect accuracy So maybe this marksman would have a 70% accuracy but with good attack speed and higher than average damage. This would make sense on a sloppy, slob-like champion. They could also have an ability that gives them greater focus and 100% accuracy for a short window. They should have superior damage over time compared to other marksmen, but they need to get a lot of auto attacks in to realize it since they're accuracy is less than 100%.