It would be nice if changing from Blender Internal to Blender game engine mode would remove all UI features that are not available for game engine.
And in turn, if there were any, game engine only components would be added.
So in short, I would love to see User Interface to be reworked to fit for game engine use when switching modes.
For example if I have a large project and I create new textures. For now, by default I end up having Texture Type Cloud (procedural), which ofcourse is no use for game engine at all.
This is just one sample and in big picture would save us many clicks and fizzling if these “mute” features were not visible in game engine mode.
This would be a cool thing to work on, yeah. It’s far, far better than it used to be with 2.49, but there’s still quite a bit that can’t directly be used in the BGE (for example, the different transparency modes in the material panel, or a good portion of the options under Options there).
EDIT: Also, it should be relatively simple and short to work on the options in the Material panel, I’d think.
I was thinking about this the other day also (want to add a “Publishing” tab to Properties for BGE mode). This would make a good intro project to coding in Blender/BGE. The whole interface is in Python so it shouldn’t be too difficult if you know Python.