Change Talon's E to a point and drag dash?
I do enjoy the thought of having Talon do Parkour over terrain, in fact that should stay in place.
What I don't enjoy is how stiff it is and how reliant it has to be on the walls of the jungle and only the few turrets and structures within the game. (It's also very limiting to see how many times you can cast it on the same surface and sometimes in the wrong positions one would like. )
His Q is a very short gap closer combined with his rake and ult, those happen to be his staples - but he has one entirely useless ability in any other role.
What if you just gave him the ability to jump by himself in any direction - having it with an increased cool down without any surface? It'd make for an interesting mechanic for him to have - since all other champions have some type of blink or dash that does damage.
It would be kind of like
Fizz's Tidal "Playful/Trickster" without damage.
Nobody really wants to initiate with his Q, so this could possibly be an alternative - and it'd truly make him feel like an assassin with flips galore!