A trailer is a means to start a conversation. After all, it's just a way to communicate with another person (hopefully many many people).
When making a trailer you need to consider:
How should I communicate to the other person?
What is the conversation I'm ready to have?
This is something I think about all the time when meeting new people, ESPECIALLY in a dating situation. Because even the most detailed profile doesn't tell me what the person is really like, and of course I want to come across as appealing as possible in a way they'll be receptive to.
How should I communicate?
This is the question behind the style of the trailer's presentation. Is it in-your-face? Is it restrained? Is it confident? Is it inscrutable? Which of these personalities best matches what you're making a trailer for? Let's think about these in terms of real people.
The in-your-face trailer could be like the person with no filter who wastes no time sharing intimate details about themselves, asking personal questions, possibly making inappropriate comments, and talking themselves up all the time. To me, this sounds EXHAUSTING. The only way I'd be receptive to a person like this is if I'd already found some other reason to like them. There might be people who respond well to this personality type, but everyone else might be turned people off. I think a trailer with this personality type are the ones for the game Broforce which are VERY in-your-face, but in a funny way which suits the tone of the game.
The restrained trailer could be someone who shares very little about themselves, so it's up to you to do more of heavy lifting. A restrained person might be intriguing and mysterious to their date, provided they're willing to put in some more work asking questions, and analyzing their demeanor and actions. For some this might come off as boring or exhausting in an entirely different way. Responding to something more restrained requires more effort and understanding of what you're seeing. A good example of this is the trailer for Sable which is very minimal in its presentation, but is very intriguing because of its setting and art style.
A confident trailer is one which is restrained, but gives you more to work with. It's not afraid to show what it is, but it doesn't scream "Look how awesome I am!" I imagine this style of trailer to be like a person who is open to questions, asks some back to you, and has a nice back and forth conversation. Never bragging, but answers honestly; nothing feels hidden, but it's not jammed in your face. I think about the recent release date hype train trailer for My Friend Pedro which is a single clip of gameplay. Confident, and exciting!
Then there can be the trailer or person who somehow manages to say a lot, but not actually reveal a whole lot about themselves. Nothing sounds terribly distinctive or unique, and no matter how hard you try it seems like you're just not going to get anything. I harp on this point a lot because it's a common style of trailer to point of features and bullet points which the game shares in common with other games. This is the game equivalent of: "I like to go out to movies, watch Netflix, eat out, stay in, and I love to laugh."
There are of course many many other personalities and styles of people, games, and trailers. What you need to decide is the personality best for your project.
What is the Conversation I'm Ready to Have?
This question is very important for a trailer's direction and the content. When I meet a new person, I don't tell them every single last detail about myself; there are things I'll save for later.
For example, I LOVE cats but I know not everyone loves cats to the same degree. I hold back my cat enthusiasm until later because I know the idea of a "cat person" carries a lot of baggage with it. Leading with "Hi, I'm Derek and I love cats!" without the context of me as a three-dimensional person means they're operating off of information they've gained from personal biases, media, and their surroundings. But if the other person ends up liking me a lot, even if they're not a cat person, it's likely they'll accept it as a quirk of mine.
Games can also have attributes and qualities which carry baggage. At the announcement stage, it's important to put your best foot forward to make your game as universally appealing as possible. For example, Supergiant Games' Pyre is a beautiful game with a rich, and colorful cast of characters; it's also a fantasy basketball game. I don't like sports video games, but I didn't realize Pyre was a sort of sports game until I'd already been pulled in by the art, music, and love for Supergiant Games. When I found out its gameplay was like fantasy basketball, I was willing to give it a shot; I might not have had they emphasized the fantasy basketball idea from the beginning.
The other reason to think about a trailer as a conversation is you will be having literal conversations with people after a trailer releases, whether with inquisitive players or press. At the announcement stage, parts of your game's design might still require a lot of iteration, therefore you're not ready to have a conversation about something which might change. If that's the case, just don't show them in your trailer, and no one will come asking about it. Make the trailer around the conversation you're READY to have, and you WANT to have. They can't ask about something which you didn't present to them.
This is just like in real life where a conversation will (hopefully) naturally gravitate towards the things the other person responds positively to. I have many interests in my life, but they don't all come in conversations with everyone I meet. Depending on the person I might end up talking about: trailers, martial arts, cooking, running a business, laserdiscs, cats, New York, LA drivers, video games, movies, anime, or any number of things!
The second trailer is an opportunity to continue the conversation. This is why making a second trailer which feels largely the same is not a great idea. How do you expect to make the conversation interesting by saying the same exact thing? It needs to be either a response or a new topic which the other person might find interesting now that they're IN the conversation.
You have to ask: What will they respond to? What do they not know which they will find interesting? Of course, there's much less room for experimentation with trailers than in a conversation, because a conversation ebbs and flows in mere seconds, but these are the sorts of micro decisions I think about when I'm in that situation.
I think this is why so many trailers come off as unappealing or uninteresting; because they didn't try to talk to us like we're people with our own beliefs, wants, and needs. A poorly made trailer feels like a person who doesn't know how to hold a conversation. Have you ever been in a conversation where it felt like the person was talking at you and not to you? A poorly made trailer often feels a lot like that. So think about what it is you want to talk about, and then think about how the person watching will respond!