3D

There's really no reason why apps shouldn't be able to rely on basic OpenGL features working. At *least* via software rendering, even if you have no 3D hardware. And software rendering should be just fine for doing transition effects for a slideshow. That apps currently cannot reliably depend on OpenGL to work is a big problem...

Luckily, there is a lot of working going on now to fix that problem, so for new apps, I too would be mighty tempted to just assume it works for everyone, or will work soon enough to not matter.