Rath has the benefit of the strongest cc out of any of the assassins in the game. This alone makes up for his lack of escape since he has fantastic initiation and disruption abilities in addition to solid burst potential. The only characters that share this trait currently are Gali and Montana (and Kid Ultra kinda, but that’s only at level 9 and he’s confirmed to be getting more nerfs). But even then, Montana has a significantly larger hitbox and lower move speed, and Galilea is just a broken mess of a character who’s long overdue for a rework.
Rath, at least in the way I see him, is supposed to be a high risk vs reward based character. He has the means to get in, disrupt the enemy, cripple their means of escape or retaliation thanks to head juggling and a crossblade slow, and deal a considerable amount of burst with his ult that can allow him to 100-0 several characters with ease. However, if something goes wrong, he won’t have an escape plan like Deande or Phoebe would. This is kinda part of his kit because if he had an easy panic button like the other assassins, he’d be a bit much given how easily spammable his catalytic smash is. His main drawback isn’t necessarily his lack of escape, it’s the fact that his passive is rather underwhelming and that his dps is very mediocre in comparison to the other assassins.
If I were to buff Rath, I would do 2 things. The first would be to either up his base dps slightly (no higher than what Pendles has currently), or revert the October 13th nerf to his ult. Only one of these would be needed to put his damage output in a good spot for me. The second would be either an increase to his base life steal, or a mini rework that I’ve tossed around a couple times before. Instead of gaining a small bit of health back for dealing damage, Rath would receive a surge of health upon defeating a target. Actual values for the amount of health received would be based off whether they were a major or minor enemy, and if it was a kill or an assist. The only prerequisite would be that you have to deal damage to the target with melee attacks or skills, so no health for turret kills or marker assists(unless you damaged them beforehand). This would reinforce the idea of him being a risk vs reward based character by requiring that he gets the kill before his passive grants any payoff, and failing to do so just puts him in an even worse position than before. This will also help him in teamfights a bit more, and make killing minions easier and more rewarding for him.
All in all, Rath is a lot better than most people give him credit for, and he’s pretty close to being in an ideal balance position. He just needs a little love to make him perfect imo.
Oh, and he’s technically not a vampire.
edit: Fixing some of his horrid helixes would be nice too, but that seems to be a problem for nearly all the characters in this game.