I know it might be late in the game and all so to speak, but I would really like to see the Assassin get some sort of ability to deal with a world full of resurrection magic and divinations.
It seems to me that anyone worthy of being "assassinated" as opposed to just plain murdered, will have access to resurrection magic, and that Assassins in such a magical world should have a class ability or special access to materials, rituals, whatever that can help deal with these sorts of things. This way their victims can stay dead, and their identities can be harder to determine.
Maybe not a flat out no resurrection ability, but a percentage or some other mechanic.