Lash is amazing at initiating fights and cleaning up opponents at low health, since his whole schtick is hitting people as hard as he can in bursts. It's prolonged fighting that causes Lash to stumble a bit. Slowing Hex prevents him from grappling away, which heavily counters Lash since his gun isn't strong enough to fight people head on. You can also dodge the stomp with warp stone, ethereal shift, or just an early dodge roll. I haven't been against the new Ult enough to know how strong it is, but otherwise Lash feels like one of the more balanced characters.
If he had to get a nerf, what would be best to make him more balanced in your mind?