Is a new IDE really required for this? Wouldn't Markdown already cover a shared "canvas" for documentation/planning, when accompanied by something like Mermaid?
I think some of the presented ideas are pretty cool, but am thinking that you'll get slown down by the IDE approach.
i think the really tricky thing w markdown is (1) tying the actual spec to the code / diffs and (2) then smoothly navigating those artifacts from one interface. markdown editors don't quite give you "go-to-definition" and nice diff viewers / code viewing affordances.
we'll be building a hosted product as well that will be web-based and I don't think that will be a full IDE, really. we really only need the ability to view code + diffs at this point, but we figured that starting from the most popular code editor in the world would be a good place to start / help things "feel natural".
also, we're not sure yet about the edit/write capability yet and how much of that should flow through here. so much work flows through the terminal these days and it's really nice to have a complementary, focused tool to that.
at the same time, i find myself missing edits + autocomplete occasionally; this is particularly valuable for specification authoring / editing, and is something that is definitely on our roadmap.
I think some of the presented ideas are pretty cool, but am thinking that you'll get slown down by the IDE approach.