unless you have some sort of "locking" mechanism happening, there's no way that your crosshair will not slightly move (mouse jitter) in between those teleports.
YES, the glitching is very sensible to almost every pixel variation...
that being said, zero?
i really don't like the delay in between failed teleports...
i used to love it when an athena has u stuck, and u just spam-away your ultimate, going back and forth and making it harder to get hit by bullets until u're free, and then u tele away...
current, if the shit that xerenix mentionned happened in game, u can almost garantee a fatality happening:
1- u teleport away to an open area, SOMETHING lets u fail it for some absurd reason, then there's a delay on the ultimate + possibility of lace showing up nearby making it worse to time ur tele while running etc...
2- u're on an edge trying to teleport across a gap... u press the damn ulti, it doesnt let you summon and u end up falling to death or significant dmg bcos now ur teleport has that ~half a sec delay, IF it actually procs ...
besides... glitching a teleport to pick up a bomb in a corner and fallback, or to scare the crap out of someone aroudn a corner and then flank them from the other side?...classics.