This is a pretty sweet WebGL editor, in the browser.
http://tamats.com/apps/webglstudio3/?scene=data/scenes/Lee.json
I think it’s built upon threejs and if you have used it, some stuf is pretty tricky to set up with code.
anyways it looks promising.
For Blender, it could take inspiration from this 3DManipulator tool, I really like how it’s drawn. Especially the highlighting when hovering over an axis in translate/rotate.
The scale is locked to all axis and yellow which is cool visual feedback.
wow, this is better than blender!
I don’t know. I think it needs more features. 
needs cycles
Shadow effect is quite nice…
Another, based on threejs lib:
http://threejs.org/editor/
and Nodes editor also:
http://idflood.github.io/ThreeNodes.js/public/index.html#example/collada1.json
Very interesting, Blender should definitely get some ideas of this.
√ Global Dictator Toolbar (you can’t live without it - File, Edit, Window, Preferences, About is essential)
√ Resource Editor Browser (no need to access materials through objects, edit them directly. How many materials your project have? How many textures? How many Meshes? How many scripts? You always need to know what is going on in your scene ASAP and no digging around to find out)
√ More useful window system (see AvalonDock for more details), like more interactivity and visual editing.
the gui is very good
why blender has bad gui?
wow wenGL really improved!