Here's something that could make the cockpits more "immersive"
1.) A light tinting pluse a light reflection. Falcon's reflections are too much IMO. When I sat in an enclosed cockpit (RV-4) I could see a reflection, but is was very faint.
2.) Nicks, scratches, and inmerfections in the canopies. They were made of plexiglass, and would nick and scratch over time. These could be small white lines and "jaggies" that we're opaque.
3.) Nicks, scratches, paint splatters, etc in the cockpit and the seats.
4.) Realistic gauges in all planes. US and British planes used the standard guages, but Japan, Germany, Italy, and Russia had metric guages. Also, have numbers and panel indicators and words (gear, flaps, beacon, etc.) in the language of the plane.
5.) Some sort of lens flare through the glass, and propeer cockpit shading.
6.) Move the gunsights closer to the pilot/move the seat up. The cockpits now seem too spacious. Find a plane like the RV-4 and sit in it. Looking straight forward, you can see the top part of the panel, the dash, nad out the glass. To see all your instraments, you need to glance down. Then you could see all you instraments, and with peripheral vision, out the front a ways.
7.) If the graphics allow it (this is just eye candy, and shouldn't be implamented if it will kill FR) moving controls and levers. WWIIOL, and WWII Fighters do this well.
8.) Cockpit lighting at night. A faint red light plus back-lit instraments (I think these were in WW2..not sure.) MS Flight Sim is WAY too much IMO. I have flown at night, and it is just a faint ed light, so as not to kill yoy night vision.
<G> Ok I'm finished rambling...