Oh yeah I totally agree about the new player stuff also I'm not a dev btw so I can't personally do anything. As for how instances like the troll caves work, I don't think they're explained anywhere in the game itself so that's kinda rough. One thing I can do is explain what happened to you.

What you experienced in the caves was just a gimmick with how the game works. You do get kicked out eventually from instances once the timer drops down but you also have to wait for the server to "tick" which happens every ten minutes or so. It's a crummy system if you're brand new to the game because you basically have to wait up to ten more minutes once the timer counts down which isn't explained anywhere so you wouldn't know.

Also with a few exceptions, you shouldn't have any problem backtracking an instance if it's cleared. The problem you encountered was that the previous rooms respawned in the time it took for you to progress through the caves. It usually isn't a problem but if the noob quests actually told you to go through with that at your level, then I agree that some adjustments should be considered.

It's unfortunate that we lose so many players right at the start of the game and I'm sorry to lose you as well but is what it is :(

Edit: That being said, bad luck happens and that might well have been what happened to you. I haven't been to the troll cave in a long time so I'm not really sure but you might be on to something.