The server tick is one of the greatest issues with this spell. It is great in concept but in reality, it more often than not, only moves a corpse.

For rescue to work as intended, it need to put an instant invulnerable on the target while it is moving them.

I would also make it a teleport to the healer, rather than a sliding move. This would address geometry issues and be more useful in raids.

As it is now, it is beyond niche and a button bloat replacement candidate. I used aquaveil more than rescue when it existed.