They're fundamentally narrative media: a landing page proceeds serially from top to bottom. What you see first matters most; like every good story, it also needs to give you a reason to proceed down the page.
It's great when they converge — where the visual design, structure of the page and the copy itself all come together in a beautiful statement of the brand's values and the product's value propositions. But none of that can happen without a story that resonates powerfully with the people who it should matter to. On a cursory examination of landing pages, it's easy to forget that they're speaking directly to a specific group, and miss the real magic simply because you aren't in that group.
Validate ideas with landing pages. Is the pricing right? Is the idea wanted? Perhaps have call of action (sign up for discounted pricing) with follow up email saying thanks and asking some question to make the app work perfect for the person. Example.