While Hi-Rez teased Vatu through a cinematic just recently, they already revealed his abilities before, making him a cooler Genji from Overwatch.
Paladins' reputation for taking stuff from Overwatch will persist with Vatu, who is a ninja that throws three kunai with primary fire and has a lengthy dash, much like Genji. There are other differences in the kit though, along with the talent trees that don't even exist in Blizzard's game.
Vatu is a flanker, meaning he excels in close quarters and has high mobility. The damage in close quarters will be 300 per 0.9 for each kunai that hits, up to a total of 900 per 0.9s. The kunai fly in an arc and have a spread so the further you are from the target, the higher the chance you deal less damage.
Alternate fire throws a small series of bombs that deal damage on impact and then some more when they explode. Unlike the kunai, these fly in a straight line as opposed to fanning out.
The first ability, Ambush, will teleport Vatu to the target enemy and deal a little bit of damage. He can recast the ability for a few seconds, in order to jump to a different enemy.
Dash does exactly what it says - propels the ninja in the direction he's facing or in which he's moving. Movement keys have priority over aim direction and it has three charges.
Nightfall, Vatu's ultimate, is a long-range dash that deals damage to and stuns enemies in the way.
With this kit, Vatu is more than capable of sowing chaos in the enemy lines while getting out unscathed, more or less.