How to fix Caitlyn
Caitlyn's main problem from the opponent's perspective is that her traps are oppressive in lane, and from the player's perspective, it's that if they nerf her traps then she would just be a worse version of the other AA marksmen. I would rather have them explore her "sniper" theme more and pull back on the "traps" theme a bit, since the traps have proven that they are not entirely gameplay friendly/fair.
Head Shot No longer a stacking ability, instead automatically triggers when auto attacking from 650(Caitlyn's max AA range) range or more. Also activates a Mega Head Shot when attacking from even greater distances. Pros: Cements range as her identity instead of traps, and allows for interesting interactions with RFC and her ult later on. Cons: Her head shots are pretty weak early, but consistent head shot pokes in lane could be OP, can't tell without testing.
Q Sends a red sniper beam forward that marks the first target hit, boosting Caitlyn's AA damage and gaining range on her auto attacks against them for the next (maybe)1-3 seconds per level. Pros: Gives her a powerful sniper ability to build around, but keeps it fair/consistent since it is a skill shot not a trap. Cons: Hard to picture the ability, maybe after shooting the beam she can hold it down, and whoever it is on upon releasing it is the target?
W Remove the head shot proc, reduce the overall amount to 1, but increase the size. Does minimal damage when sprung but additional damage to minions. Pros: Less traps, can still be used to snare, and can be used to damage minions, replacing some of the wave clear lost from Q. Cons: Needs to be larger to damage multiple minions, but still not so large that even just 1 traps could clog up lane.
E Relatively unchanged, since it already does a lesser version of what her Q does.
R Temporarily Increase the range of the Sniper Beam from Q greatly, and also allows the beam to reveal the fog of war. After landing the skill shot she can head shot at the target from far as hell away, and since they will be over 950 range, her head shots will be the **Mega Head Shots ** Pros: An overall better ultimate for the enemy and player, since it can be both dodged and blocked now, but it gains more power for the player to compensate.
Mega Head Shot Would root her when using it, but it would be more powerful than a normal head shot, and make a much louder sound like the loud bang of a real sniper rifle. Maybe even penetrate enemies for lesser damage, but don't wanna over do it. Could be made so when combining the range increase from Q/E and RFC that it's possible to pull off one Mega Head Shot without the ultimate.
Pros Possibly the most deadly champion from her maximum range in the late game. The majority of her damage amplifying abilities are linked to a skill shot (QER), and being a certain distance away, making them powerful with the counter play of getting closer to her. Traps a bit larger, helping her keep enemies at bay a little longer so she can stay at max range but are far less oppressive in lane. Unable to brainlessly AA to win, requires careful positioning and a range mini-game unique to Caitlyn.
Cons Power drops off significantly when closed in on. Really comp dependent, if the enemy can close in on her easily she'll struggle hard, but she'll annihilate them if they can't. Relies heavily on landing her Q. Her Attack Speed may need to be tweaked when from a distance, so she can't shoot head shots like candy late game.