I rarely post on these forums as half the community here make me sigh in disbelief but this caught my attention.
The Thief is annoying but if they weren’t I don’t think they would be considered a Thief. The mobility and option to pop out of view (within reason) is the backbone of the profession: If we aren’t buzzing around you like a bothersome fly that won’t go away then we’re not doing it right!
There’s a trait bonus that grants us 15% endurance back after we dodge meaning (with a full bar) we can evade 3 times in 5 seconds and some weapon sets offer poor damaging + evade skills but burning through those leaves us in a worse situation if we actually want to escape and we won’t have any initiative left to do something fancier than auto-attacking. As for stealth, well, you might not see us but you can still hit us. Several times I have been downed having just entered stealth because the opponent predicted where I would be or used some AoE on where I was last seen. You might have also been standing in a black powder pool generated from the pistol 5 skill which applies a small AoE blind for 4 seconds. Generally speaking we have low toughness and a lower health pool as well so when you can hit us it does hurt a fair bit and if you’re facing a berserker Thief then any landed hits will make them melt faster than butter on the surface of the sun. In some respect we are the definition of glass cannon.
You mention being 3-shotted and automatically I think you’re exaggerating due to understandable frustration but if true then I have to assume you’re some kind of low toughness/vitality build and had been attacked by a full berserker Thief. In that situation 7-9k backstabs and 3-4k heartseekers aren’t unheard of but landing that particular scenario isn’t easy unless the target is stationary and not looking around. First we’d need to spot the target and then hide behind structures until they get closer or stealth to avoid them seeing our where-abouts. Then we’d need to catch up to them whilst remaining unseen which is often a bad joke unless they are running nearby. There are perma-stealth builds so in theory you can tail someone in the open while remaining unseen but the mandatory stopping to “top up” means our travel speed is severely hindered and chasing a constantly moving target is genuinely impossible (plus a keen eye can spot our tell-tale black powder rings, so even then there is still a way of knowing about our presence). It’s nowhere near as easy as you might think!
To mirror the other replies, more toughness would greatly help in such situations. I guess in some aspects it’s that age-old “rock paper scissors” deal and generally speaking a berserker Thief will beat a berserker anything else if he gets the jump on him.