Twitch's q is not what needs buffing

It's a super strong skill already. it's his attack steroid, a perfect escape if he gets it off and the enemy has no pinks, and provides very low counterplay initiation and great repositioning in team fights.

There's a lot of room for fun and interesting buffs in his kit though. Let's look at his other skills:

Venom Cask - Provides some wave clear, but is useless late game. It does nothing, aside from slowing a straggler to get one more auto on them, but even then, Twitch has to stop and cast it when he could be moving. Buff Idea: Remove it's cast time, make it like a Syndra q,

Contaminate - Great skill for early all ins, but it gets pretty bad as the game goes on. It's more productive to auto attack late game. It also costs too much mana to harass or farm with. Buff Idea: Contaminate refunds half its mana cost if Twitch kills a unit with this skill.

And for the ult, Spray and Pray, whatever you'd like to call it, just doesn't do enough damage. On top of that it's clunky to use unless kiting backwards because the autos cancel easily and can be dodged by running out of range. Buff Idea: This skill I think is in the most dire need of buffs. Either give it -Armor penetration -Contaminate's range is doubled while this skill is active -10 seconds active time. It's currently 7 at all ranks. Its duration could even scale up by level like 's ult. 8-10-12 seconds

tl;dr needs more to compete with other hyper carries, because right now, he just can't stand up to or in terms of reliable damage.