I have been writing web apps for Tornado server for a few years now, spending more time on client apps than system apps. For the most part the system apps are feature complete but working with them every day even being able to shave a few seconds off each task overall saves a lot of time. Today I added a huge feature to the /system/webdesign.pma app: The ability to edit the application design using only a web browser!
Why is this so important? For starters, making design changes is now very easy and can be done from any PC on the planet with a modern web browser. Second, developers trying out the capabilities of the server can easily get started without the additional pain of installing client-side development tools. By no means is this a replacement for the Vortex IDE we have in development, but really bridges the gap between the patchwork of tools we currently use and the comfort of a dedicated IDE.
We live in interesting times!