I know, at the time when those guys played, they had about 40%-45% crit, not fully 550, but whatever proc they were on they had their crit increased by like 125%-130%.
This dude's different, the uptime he has on his crit for that long, he at times don't have to burst or open on you, and when he does burst he hits hard. The weirdest indicator is there is a constant sound that keeps ticking whenever this guy fights, the longer you fight him, the more you hear it.
As for the use on SP, his poison dots that tag you will do some big damage, if you are a ranged dps, there is another poison that tags you and slows down your dps for several seconds for like 5%. Something that was never done was he was able to sometimes hit through a hunter's deterrence when he really gets off on you or randomly put you to sleep when you touch him. All I know is he originated from the twink community, we use to chill with him until the bracket died months ago.
Other then that when it comes to crit, you won't be able to hit 100% all the time, except for the 3 players mentioned. Buffs won't get you that far either.
EDIT
he has a thing for trick armor and gear so he can be brought down if you cc him quickly. strong, but a reckless rogue who uses troll tactics too.