FlightGear 2.8 will be released on this August and the developers still the have time for many improvements and additions. One of the biggest things of this release will be the finishing (hopefully) and inclusion of the great enhancements that the Rembrandt Project will bring to the best open source flight simulator.
What is this about?
The idea behind the project is to replace the current forward renderer that FlightGear utilizes with the implementation of a deferred renderer. This basically means that the lights, shades and shadows will be greatly improved in version 2.8, as they will be rendered in separate computational stages (Geometry, Shadow, Lighting) and combine the optical results on the final display stage.
As you would expect, the video memory usase will increase, but one can always setup the preferences.xml to reduce the size of the shadow map.
One more technical detail is the inability to render transparent objects, so the clouds will be rendered using the classical method.