@1: No I'm not a member of the ED team. I do other projects... at the moment nothing graphics related.
@2: No. It should be totally possible. But I'm not an expert in flight simulation engine design. But in the end you have: terrain rendering, water rendering, entity rendering, sky rendering, sound rendering (I read somewhere that they use one thread for sound exclusively in DCS 1 for advanded effects like sonic boom, can somebody confirm this?), cockpit rendering, physics, networking... so nothing totally different from other game engines like Unreal Engine, CryEngine, Frostbite and what not. But a flightsim engine have to has a very good scaleable terrain/entity renderer because you have square kilometers of playfield. The DCS 2 demo videos I saw the last week where very impressive. The terrain looked good from every altitude. You even saw curvature of the earth.
@3: The operating system kernel is clever. At least earlier in WinNT and since Windows Vista/7 again. As far as I remember they did a complete new task scheduler for Win7 based on WinNT. Something like this. So the engine, If there're enough hardware threads, could set affinity for heavy load threads which then run exclusively in one hardware thread. I dont know what DCS 1 or 2 does... will do.
@4: Could depent on 2) based on how your game engine works. This topic on it's one is heavy science. You can spent years developing a bad ass engine... see Unreal Engine... Cry Engine... the cost-benefit ratio must be given for this. On the other hand engines like Unreal and Cry are very flexible engines. At least for now DCS is very aircraft concentrated. We got closer to the ground with the helicoper simulations and even closer with Combined Arms. So here things must improve. In the interview on mudspike Waggs mentioned something in this direction. So if you want to drive a tank over detailed terrain or walk soldiers. You need some addional things in your engine.
If they would start today with a new engine the base facts didn't change. Multi-threading is nothing new. The only thing which could lead to an adapated design is the knowledge the developers gathered while developing DCS 2.
@5: Didn't know about HSA. But yeah... the text content is not that new. At first we had GPUs which where fixed to rastering triangles. You had some register combiners to manipulate color. Transformation, Clipping, Lights and fog where baked. Then the vendors realized that it's better to have a more general GPU design. So the (nearly) general purpose GPU architecture combined with shader languages where born to be able to write SIMD kernel (vertex-, pixel-, geometry-sahder) for the GPU. This indead ended in CUDA and at the end in OpenCL. We created a parallel universe CPU | GPU. Companies tried to give developers tools at hand to utilize the amount of available CPU hardware threads with libraries like Intels Threading Building Blocks. The HSA article to me sounds like the next stage of Intels Threading Building Blocks. Yeah games will profit from it. But the developers have to adapt. For example on a playstation this kind of heavy multi-core programming is standard.