Overall I think Rath is in a good place at the moment, considering many CC’s totally wreck his ult since it takes several seconds to fire off the whole thing. and he is made of paper mache at best. When playing against intelligent players you need to be super careful both as him and against him.
A lot of people compare his ult to other high damage ults like ISIC, Thorn etc… without considering the fact he is a fragile melee character. If he could fire Dreadwind across the map I’d agree it was pretty OP.
If you are on a slow fragile character and he catches you off guard you already had your chance to counterplay him by not being in that situation and backing off. If your team communicates things get even more difficult for him since he essentially has to sneak past 5 sets of eyes to get to the battleborn he actually wants to fight.
Faster characters like Thorn and Orendi or tanky ones like Isic and Montana can all beat him easily while maintaining range even if he manages to close the gap. You are pretty much free XP to a well played Benedict as well.
If they lowered his Dreadwind’s speed everyone would just walk out of it and he would get shot to pieces every time.
All that said I think his kit is a bit backloaded into Dreadwind and they could likely remove some of his damage and put that power elsewhere. Which would keep him viable while lowering the frustration newer players have from his ult.