Nerf Assassins!
But buff them!
Wut?
Nerf assassin's early game, but buff their late game!
It's just silly and poor design that first: Assassin are really strong lane bullies with ranged poke and mobility to escape gank or engage. Second: Playing assassins really does require little thought because as soon as you hit 6, you can dive almost any squish and 100-0 them.
Yet, they're not overpowered, why?
They become so irrelevant in the lategame. Just throw an exhaust or a stun at them and they die or escape without killing anyone.
Just nerf their base damage, that way they have to work harder to get kills, or roam and find low health targets to execute. This promotes better counterplay and intelligent decision making.
Also buff their abilities' ratios, this way their damage will scale harder into the lategame and they'll stay relevant while not being faceroll bullies early.
Currently assassins make me sad whenever one gets really fed early, but fail to kill a single person if the game lasts long enough. It's just really poor design especialy when most assassins are working that way.