http://nexgenflightsim.com/wordpress/?p ... dy-writtenwhile the discussion in the 2nd link is interesting - the OP is apparently somewhat familiar with FG, and simulators as a whole (the term "IG" is telling) and FlightGear's architecture/issues (fgCreateSubsystems), but also pretty ignorant of any licensing issues resulting from adapting GPL'ed code for a proprietary project ...
And many things considered "modular" and "reusable" are far from being that.
And doing what he/she suggested, replacing the scenery engine, has been done already - just look at poweroftwo's osgEarth work ...
Overall, it's a neat little discussion, but also a little ill-informed - however, it will be interesting to see what happens to this. In these days, you can accomplish tons of things with a little crowd funding and project coordination, i..e they could certainly bootstrap themselves without being subject to some of the more rigorous constraints that FG suffered, is suffering, from