I'm not entirely sure how the game expects me to figure out what to do. I reached a point where I pretty much knew not what to do to get the story moving forward. I train a bit. I go out and fight monsters. I got the dispel potions, had the vision in the temple and quickly lost track of whatever the hell I was supposed to do.
People attribute weak pacing and unobvious triggers to QFG3, but most of those are actually scripting bugs that cause hints or conversations to not appear, which leaves you having to guess what to do or consult a walkthrough. I'm not excusing them because stuck is stuck, no matter the reason, just pointing out differences between bad design and bad QA.
Eventually, I had to check on a walkthrough : apparently, I needed to give food to the thief three nights in a row ? The hell ? How is one supposed to figure that out ?
The thief is supposed to come to you (you really can't miss it; the game goes in cutscene mode when he approaches you) in the market, during the day, and asks you to come talk to him at night. When you do come back he says he's starving, and if you give him money he even emphasizes it's useless to him because nobody will sell him anything. Figuring out you should give him food is pretty obvious at this point. And when you leave he begs you to come check on him again - another hint. Unfortunately the initial daytime cutscene script fails to trigger sometimes, and so you never know he's waiting for you unless you randomly walk into the market at night.
Then I hear a prisoner is supposed to appear somewhere ; but to trigger this, I have to... train my spear throwing skill ? What ? Well, he's still not there, I guess I'll train some more.
Not quite. Each class is told of a class-specific thing you need to do (train for the initiation ritual, get the mage staff, or sneak around and try (and fail) to find the Lost City). Part way through these the prisoner appears. It's not as unobvious as you think... unless some scripts fail to trigger, leaving you wondering what you're supposed to do next.
And how was I to figure that this one time, because there was an empty extra seat in the inn, someone would show up and talk to me while sitting down was always a useless action ?
This is the only one I'll actually disagree with you on, because I never even imagined someone having trouble with it, and it's certainly not a complaint I've ever heard in the 27 years the game's been out.
Did I miss something ? Was anything about this hinted anywhere ?
Pretty much of all them are
supposed to be hinted, and most of the time you can't actually avoid seeing the hint... unless a scripting bug occurs.
QFG4 is notorious for bugginess, but QFG3 wasn't much better. I think the only reason it got a (relative) pass was because none of the bugs were actually game-breaking. They do make it very hard to play blind unfortunately.