Some of it, yes. E.g. the clues: more just happening to show up every time the players miss too many is Not Good. But missing clues can mean the guilty continue to act unimpeded, so more crimes might be committed off-screen. (After all, "think off-screen too" is a DW principle.) Ultimately, the sequence of events matters, and that'll be complex, mixing in- and out-of-game things. Using the murder mystery from my home game, I prepared six distinct clues, and would never have added more (because the point of the murder was to disrupt the court, not stick around and commit more crime). The party then had the responsibility to question and learn. There were false leads and a single perpetrator, not a nebulous "whoever you think is guilty actually IS guilty" thing (which I consider to be illusionism of a different color.) Their results, right or wrong, would have significant political and diplomatic consequences. Knowing I couldn't prepare for all possible accusations and consequences, I prepared loosely for a variety of options but kept myself open to change.
That's...complicated. On the one hand, if the party had failed a lot or been untrustworthy, he would never have told them. But a meeting of some kind was inevitable, for three reasons: (1) Shen is hunting the black dragon (a front), so as long as that threat remained, Shen would be relevant to the party; (2) his fiancee is Hafsa el-Alam, a trusted ally and confidant of the party ever since she gave them their first job; (3) he's only in town because the Safiqi priests (the dominant religion of the region) requested him, and the party has closely worked with the upper echelons of the Safiqi. By taking these allies and opposing the black dragon, the players made meeting Shen inevitable. The reveal didn't happen right away, it took a while for Shen to feel it was worth the risk. The party had made active efforts to earn his trust, and in turn, he saw that the party had a lot of potential and wanted to see them grow.
I had feared my players would hate him. Thankfully, they found him interesting and mysterious immediately, and then later they started shipping him and Hafsa. I'd have been sad if the players had rejected him, but would've bowed and left him as background. The black dragon would still be there though, and because the party would be ignorant of the threat, the dragon and their gang would be able to act with impunity for some time before the party learned of their escalating activities.
I did not, no. Several of the revelations have occurred in contexts I never imagined even six months ago, let alone three years ago when I started this game. Some were improvised on the spot, others from careful thought and prep. E.g. that "why devils are Always Evil" thing I blather about came to me...last year IIRC. I already had four obvious sources for who would tell this story: a devil the party has worked with named Al-Ikhino (an arabicized "Alichino," from the Divine Comedy), the party bard's succubus great-grandmother, or an expert/book from a Safiqi or Waziri institution. None of these were the true first glimpse. Instead, a character accidentally had a soul connection with a (different) succubus as she was dying, the result of a partial success on a roll, and saw the darkness within. Wanting to know WTF that was, he turned to the bard's family, specifically his mother. I hadn't thought of that, but she made perfect sense. The party also consulted Waziri texts and Al-Ikhino for further details (the broad strokes were the same, but each group drew different conclusions.)
I work to make sure (a) the info is there, (b) there's at least one way they definitely could learn, and (c) that one way is not the only way to learn. Any person, place, thing, or event that depends on one and only one sequence of actions is always to be avoided. If I ever run into such a thing, I step back and re-work things as much as possible to avoid it. If there's genuinely no possible way around it for some reason, I'll be frank with my players that I have screwed up. (I am quite open about mistakes I make, though usually only after a session is done.)
I'd hate to learn that my players did a thing solely because they thought I wanted them to. I do have OOC expectations of courtesy etc., but I'd feel like a huge failure if my players ever said, "Oh, yeah we did that only because we thought you wanted us to." The very first adventure--Hafsa offering a contract to investigate a recently-discovered ruin--did have a little bit of "you're all okay with this as a starting adventure, yeah?", but many campaign starts are like that, so I hope that is forgivable. After that, I used other hooks. Family members making requests, Hafsa discovering something in her research, the Sultana requesting the aid of adventurers that had already helped protect the city, a friendly NPC disappearing, etc. Things I truly hope weren't done because I wanted it, but rather because they found them interesting, or felt their characters would respond to them in adventuresome ways. Edit: And, of course, the times the party has gone searching for stuff to do entirely as they liked, such as "what's on the contract board today?" (cue me making up three contracts) or "hey, that one archaeology librarian we know, does he know any abandoned digs we could check out?" (inventing an archaeology dig on the spot...with some fun surprises baked in) or "I want to find homes for those people we rescued from Zerzura. What does Fahd [important priest NPC] need so that can happen?" (led to the above-mentioned murder mystery in a Jinnistani noble's court)
I can say that two different players have, separately, said that they value the fact that they COULD choose to just say, "Nah, none of this is interesting anymore, we wanna take a boat out to the ocean now" or the like, and that I would roll with that. It would be pretty disappointing, but I'd roll with it nonetheless.
