Can I suggest improving the hints and usability around the admin UI? Some of those boxes give no indication of what to enter in them.
Also, terms such as Rewrite URL aren't hugely clear and Josh explains them as the URL template of your back-end service. I often see this in UI design; jargonistic terms on the UI and then a human explaining what they actually mean, instead of just writing what they mean in the UI in human terms to begin with.
Finally, consider using diagrams to help convey the architecture and flow. I say all this because a new client of mine use a well-known competitor's API management system which is very hard to use, essentially has just a bunch of fields scattered over several tabs.
"According to one stat from 3M Corporation and Zabisco, 90 percent of information transmitted to the brain is visual — and visuals are transmitted to the brain 60,000X faster than text."