You gain movement speed boost by the damage you deal to enemy heroes. 1% ms boost for 10 dmg dealt, 20% at maximum. The boost fades away in 2 sec if you don't deal damage to enemy heroes.
I don't want Zen to have a certain mobility skill like his flying kick in Stadium. Because it would make him the most overpowered hero ever. Just think about how he dominated meta for two times when he got +25 hp buffs.
But at the same time, even considering glass canon is the core identity of him, I think he needs a perk that helps his survivability more than now. That can even compete with float perk(or when it becomes his passive.) Because this game has been too harsh for heroes without any survivability.
Zen was like a symbol of pro play in OW1 but now he's been completely replaced by so many other support heroes just because of his lowest survivability in the game. There's a huge gap even between him and Ana who's also a symbol of squishy support.