I looked at those examples, and considering my experience with lining up backstabs in TF2, or melee attacks from behind in Tribes Ascend, I honestly think that’s pretty fair considering his role.
For a guy who’s built for sneak attacks, the timing need to be a bit loose, because the tighter and less forgiving it is, the easier it is for people to just dodge you entirely. Which is pretty frustrating since you have a limited range to use it as is, even shotguns have more range.