I have participated in a lot of Mystery Knit Alongs (MKALs) over the years. Some have been awesome. Some less so. Part of that is what you sign on for, the project is a mystery after all. Some turned out to be more or less work than I was ready for. And some - were just not meant to be mysteries.
See, the idea with a mystery knit, is that you are getting the clue in pieces. Not every pattern needs to be modular or pick up and turn from a circle to a square, but part of the mystery element is that it won't look exactly like you might expect if they just gave you the first clue and said, go forth and knit.
So, quite honestly the worst mystery knit I ever did was the one where clue 1 was do X with colors 1 and 2 and then clue 2 was do X with colors 2 and 3.
I think serials are often like this. I think most authors understand that a serial installment should leave you curious about the rest of the story, but sometimes they do that rug pull thing at the end and then undo it right at the start of the next thing. And you can only do that so many times before I know that everything you tell me (much like reality show episode teasers) is going to be less bad than you are pretending and now I don't care. But the opposite is also true. If you write a book, and just break it into equal parts, that's not really a serial either. That starts to seem like you are trying to get me not to notice how much the whole book cost. Now Serial Pub has some serials where each episode, focuses on different characters, so in that case it's less rug pull and more, oh, now I get to find out what the gardener was up to, which is another approach.
But the overall message I have for both pattern designers and authors is that not everything is ready to be a serial or a mystery knit. And it doesn't have to be. You can give me a normal pattern, a novel or series of novellas, and I will happily decide it it's for me. Using a format your story or pattern isn't suited to, does no one any favors.