The app interface is intuitive and the learning curve is not steep. Within the first hour of app use I was able to assemble a basic presentation that still had the wow factor. Storydoc has plentiful templates to choose from and I personally found the storydoc internal branding to be pretty unobtrusive.
The app has a bright future if it continues to expand its template offerings, and adds further customization features to maintain the wow factor. Building in a presenter mode, and having full nested cards that allow zooming in on details would be nice. (See Gamma app, and prezi for examples)

Is there a place where users can request and vote on proposed added features? Is an app changelog available?

Overall Storydoc is already an impressive app that seems feature-wise well positioned in the market. With additional development hopefully it can become a household name.