Source code user interface upgrade
So, you know how when you View Source in a browser the code is displayed in different colors to indicate what different elements are? That would be really, really awesome to have in the Content App's Source Code view. Bonus points if you can get the code to display in it's actual hierarchy.
The thing is, when you need to go tinker with something in the source code, it can be difficult to find and keep with with things with the current, black and white, blocky space.
And, if you wanted to go even further, you'd make that window that pops up expandable like a regular browser window so a user can really stretch it out to see the big picture.