Coda is one of my preferred apps. I use Coda almost every day and can not imagine to dispense it. I even would say coda is one of the most advanced and dynamic application for its primary purpose.
Anyhow, I think Coda has the potential to replace a lot of other apps. Many people use other apps for more specific tasks.
To take advantage of Coda’s immense capabilities, it would be important to apply all current capabilities of pages to text cells in tables.
In addition, it would be great to be able to ad backlinks as you can do with Roam or Obsidian.
There are many small things other apps do better. In Quip for example you can add URLs even to page titles. You can easily use anchor links, and add comments to images or any marked part of the image.