Dave writes:
What if you could design, create and edit a stack in a single outline? That's what I have working. Instead of the runtime being Hypercard, the runtime is the Web.

I have a problem with this… I learned to program using HyperCard and HyperTalk. What Dave has working is HyperTalk in an outline, with placeholders for GUI elements. Frontier has a great outliner. I won't dispute it. But an outliner is not the place to develop visual interfaces.

Dave also says: Give this tool to a writer who loves writing, and all of a sudden the complexity lifts, for the user, because it's lifted for the writer.

But HyperCard was not a writer's tool. A writer does not want to care about where stuff goes on the page. HC was a software developer's tool, used to create elegant, sophisticated multimedia applications. Yes, many people we developers would call "users" created awesome stuff in HyperCard; in doing so they were taking the role of developer.

I love writing code in an outline. I even like creating presentations in an outline. But when it comes to mixing outlines and layout, I'd have to say that PowerPoint is the closest thing to HyperCard + MORE. Granted there's no runtime, but that's the format I would want – outline and layout side by side.