I totally agree with what Pherp is saying above : you must be able, for any simulation you offer (flight, ground, sub, etc...), to provide the best visual experience :
Please offer full 360° immersion, 360° field of view, Horizontal and Vertical.
allow the user to set up multi views driving multi screens/projectors.
Of course, I do not think that very large FOV with high resolution is today feasible with only one single CPU (even with several GPUs).
By the way it is NOT feasible neither in FSX nor with Prepar3D,
so implement multi-channel Image Generation with networked PCs sharing the same world/LOD/point of view.
Dear Cameni, about my above "marketing / competition " comments, I know that you are not naive at all and as BISimulations main team is closed to you, being in Europe does not mean being in trouble at all,
However I wonder if we, European, are still capable of funding interesting advanced startups/projects? I hope so...
Finally another question : is there already any real 3D simulator (stereo viewing) on the market ?
we have 3D screens, we have 3D capable projectors... what if ?
For the rest, many members have already answered but focus on what you are the best at,
then open your engine for add-ons and/or look for partnering with others who are very flight specific...