In its current state spirit of vengeance is not unbeatable but it is a massive grind and timesink Here are some of the issues I personally have with the flashpoint. 1) The trash mods are overturned and have way to much health. It does not help that many of trash mobs also shield themselves and have stealth detection. 2) The pacing is off. There is a huge (trash filled) gap between Gorga Brak and Bask Sunn. The last two bosses Troya Ajak and Heta Kol are basically back to back. 3) The bosses are badly designed, at least in story mode, Gorga Brak will instant kill you unless you interrupt his full auto attack. If you messed up and your interrupt is on cooldown, your dead. Bask Sunn rocket punch ability also instant kills but unlike Brak's full auto you can not interrupt it. The only way that works for me is to kite him around the room and pray to the RNG gods that he does not use it when I have lower health. Which is not fun for melee classes. Troya Ajak and Heta Kol have the opposite problem, they are both weak as hell. Both these bosses are face rolls. Heta Kol will turn invincible and summon trash (Literally my least favorite boss mechanic btw). The trash phases are hard, because the trash in this flashpoint is too powerful. But when you are actually fighting the boss, no problem. As for Troya Ajak, she the easiest mob in the flashpoint. Which is a huge problem for a boss.