The bloodletter is abused for killstealing, where a 4.2 or even 4.1 with max specs will deal insane amount of damage to finish off players. It does too much damage for the mobility and the cooldown is 17 seconds or lower with cd reductions.
Bloodletter as rat used to be fine, since they would need to survive after getting the kill and loot (was kinda easy because soldier helm, miner boots, undead cape, assassin jacket etc etc and if busy in a fight dealing with rats is not the prioirity).
But ever since the faction warfare update, these rats are even running cloth to secure kills steals and loot. Hanging around camps all day to leech off the chest, any fight breaks out they safely follow and killsteal. Repeat.
What's point organizing an entire party to fight just for a rat taking the loot and pvp fame solo???
The bloodletter is to blame. Enormous amount of damage with no need to stack anything, can be at a safe distance, low cooldown, good mobility.