I want to add the importance of what Tom Schülke said. For an Architect the automatic update of a pdf is essential. Updating one by one with "replace" is not convenient enough. And being able to select a color from a PDF without copy it and rasterize (Tom Schülke idea of a live filter seems good, although being able to do it directly like PS would be better) is also a very important. Like it was said, in the architecture's workflow one has to assume that everything is always being updated and one should be able to accommodate those changes as fast and smooth as possible.
I hope soon this will be possible. A whole market could be (more) open to AF.