tl;dr thieves are fine, however lack variety. Don’t nerf, will be useless class. Look for ways to give thieves more playstyles.
After reading this thread, I am going to assume ghaleon is pretty bad, or possibly using information based on very few fights. Scepter focus zerk ele vs zerk thief (any) is actually a really fun fight, requiring fast reactions, and equal skill from each player! I know this because I main thief and also ele, and I am also a moderator of a gambling duel server. I watch many of the best players duel, and one night, I watched one of the best fresh air eles, and d/p thiefs duel over 30 times, sharing wins back and forth all night. I KNOW for a fact that fresh air and thief is a pretty equal fight, and much more entertaining than watching a cele v cele fight. Also, the ranger vs thief is pretty balanced in a situational matter. Generally, the thief has to be smart about his stealth, escaping when invulns are up, avoiding CC (the longbow push back, pet fear, forcing ranger out of longbow). The thief can easily burst a ranger down if he’s stuck in melee and has no more active defense. However, in a team fight, I believe the ranger has a BIG upperhand, because not only does the thief have to decide to attack the ranger, or another target, but if the thief chooses not to attack the ranger, the ranger can roll him in seconds. If he chooses the ranger, his teammates can peel just enough for him for the ranger, to again, roll him in seconds. Zerker mesmer seems to still have a few issues with thief, but I’ve seen mesmers win fights versus thieves as regular shatter. I’m beginning to think shatter may not be the best way to fight a thief anyways. I noticed signet builds handling thieves very well (condi or zerk; condi being off topic, sorry). I feel like thief is in a “decent enough” position right now. On a scale(100% being fully op, 0% being fully underpowered) I believe thief is about a 40 – 45%, due to team fights. In 1v1 situations, I think they are about a 50% – 55%. I’d like to see a thief build that relys more on staying in the fray of combat, dealing good damage over time (not overly bursty), without having to rely on “stay away from combat until target is at 50% hp then burst” as it feels skill-less, and silly because you don’t necessarily have to avoid most of the skills in the team fight, instead, your burst for a few seconds and quickly stealth/range/los back out of combat. I’d enjoy thief more if sword/x was more effective (not like acro/trickery opness) at staying in the fray of combat. Thief is still to squishy to sustain in combat, and if built to sustain, you become subpar (other classes will mitigate better and still deal more damage). I’d like to see different ammulets become more effective for thief. Such as soldiers, barbarians, knights, valky, maybe even rampager, without being too tanky, and still lacking damage. This would be almost impossible because d/p variants could always escape and never die if you give them a hint of tankiness. I feel like the thief playstyle is currently pigeon-held into one style. Elementalist, engis, rangers, warriors, necros, even guardians, have WAY more variety than the thief has available. Haha, notice the only class I didn’t mention was mesmers? Mesmers and thiefs have terrible variety, so requesting to nerf the only thing thieves have going for them, is going to turn the class into a character slot thats always going to sit all the way to the right of the log in screen(no ones going to log on into their thief).