In the newest patch Riot is changing to play style of the second assassin they added to the ranks of champions in the early days of the game. Riot is making strides to improve Twitch to be a much more aggressive rat, in an effort to make his ability to pop out of stealth and murder someone much easier for the player. Riot validates this in the same way they did with eve, by citing that the ability of Twitch to remain stealthed for so long made the opposing team focus more of defending against him than anything else.
One of the strongest problems Riot felt was present in the current Twitch build was that players felt almost obligated to remain stealthed until they had the full attack speed bonus of Ambush. While using Ambush to its potential was the quickest way to put stacks of Deadly Venom on someone. For those who did not play Twitch, Ambush was his stealth that provided a growing attack speed buff the longer he stayed cloaked. This promoted the player to remain cloaked longer than what was reasonably required for a team fight for the extra few points of speed, and sometimes cost kills if a player did not attack soon enough. Riot wants to remove this uncertainty of speed bonus vs. the need to unstealth and attack. Plus, as an aside, Riot noticed and got tired of players not being able to farm while being forced to remain stealthed for a bonus.
Riot wants the rat to be an aggressive carry and so is redesigning his stealth to be focused on winning a fight through quick repositioning as opposed to “Kay, I’ve been invisible forever, time to let my attack speed bonus carry me.” Ambush now has a much shorter duration, forcing the player to use it more tactically than they were previously. Ambush now always has the maximum attack speed bonus while stealthed, allowing for the player to come assassinate others at their choosing, and to help with this shortened duration, the ability now comes with a move speed bonus to let the rat close in on people he plans to kill.
Another problem Twitch had was the over dependency on his ultimate to deliver the killing blow. Too often, Twitch came down to a champion that changed games if he landed his ultimate and cost games if he missed. Riot wanted players to focus more on the interaction between Deadly Venom and Expunge (which was always potent on its own) but the sheer damage put out by Venom + a full on Spray and Pray barrage was enough to shred most champs. Since Riot wants to mostly focus on the interaction of poison combos for intensive skill-based play, Twitch is being given a new ability to help him along.
This new ability replaces the previous initiator of Dehabiliting Poison, and is basically an AOE attacked to slow the group of his targets. (Similar to Cassiopeia) that gives a head start to the Deadly Venom combo by applying venom stacks to the enemies it hits. Twitch is also getting a significant buff in the form of Expunge no lower consuming the current Deadly Venom stacks off targets. This allows Twitch to continue to apply damage after his poison combo, as opposed to previously pressing Expunge and hoping it was enough. After all, when the champion had escaped except for the Expunge activation, if they did not die they got away scot-free from the Venom stacks being consumed? Now? Watch that poison be like the Energizer Bunny and just keep on going.
The final step to buff Twitch was to give Spray and Pray a new purpose in combat with a focus more on setting up the poison interactions. Thus, the ability is receiving the same nerf a lot of AOE cone abilities possess of having each individual missile do reduced damage to each target it passes through. Riot is attempting to balance out the overall lower missile damage by increasing the speed that each fires while removing the ammunition requirement and lowering the targets chance to dodge. While Twitch is now able to use his ult the full duration every time, the reduced damage to subsequent foes will allow a tank or bruiser to soak a lot of the damage in a team fight but still will soak the juicy targets in Venom stacks.
All in all, I like that Riot is focusing more on applying and keeping Deadly Venom on the target. After all, he is supposed to be the Plague Rat so it makes sense to have him be built completely around poisoning his foe to death in a slow and gruesome way instead of the fire-and-forgot method of expunge. Kudos to Riot.