There are probably more forum posts and e-mails regarding realism than any other subject for FS, so I thought it might be useful to post some of my thoughts on what realism is all about. And btw, this is all just my opinion, and doesn't necessarily represent anyone else on the FS team.
We have a lot of users that are experienced real-world pilots, and truly do know how a real aircraft flies and reacts in various conditions. A few of those pilots actually have first hand experience with the specific aircraft we include in the product (although most real pilots have at least some time in a Cessna 172). As the aircraft becomes more complex, has greater performance, and costs more in real life, the pool of users that have real time in that make dwindles to a tiny percentage of our overall userbase. Not many have time in a 747 or a Lear Jet, much less the historic aircraft from FS 2004.
So what's my point? The point is that I'm guessing most of the noise on the forums about how wrong flight models are have very little knowledge about what is actually right and are basing their opinions on other user's opinions. When it's based on the opinions of those that actually know, it's probably pretty sound, but as information is passed from one to another, some distortions are inevitable.
I think the bottom line is that everyone's idea of what is realistic is likely a little different. Even for real pilots with stick time in aircraft we provide in the box, there are differences of opinion on how an aircraft should behave in specific conditions. We have arguments on a regular basis on our own team between people that have both flown the real aircraft but had different experiences.
With this in mind I think of realism a little differently. I think there are three components which define realism.
Fidelity is the degree to which any given system or behavior is simulated. You can model something with very high fidelity and cover every behavior or with low fidelity but get the most important behaviors.
Accuracy is kind of obvious, but is how close the behavior of a system is to the real-world. Exact accuracy should mirror what the manual for the aircraft flight behavior or a system says should happen in a given scenario.
Authenticity is a different kind of beast. This is where the emotion comes in and wraps up the experience as truly believable and appropriate. This could be as simple as exhaust soot on the airframe or the sounds the aircraft makes.
All three of these elements combine to make for a realistic experience. We could model a hydraulic system with great fidelity, but not have accurate pressures or accurate behavior in a failure situation. And if an aircraft has super accurate rivet patterns and panel lines, who cares if it's presented with a lame livery/skin. All of it has to be balanced to create an overall experience that works well for all users.
As I've said in the past, we ship such a large number of aircraft in the core product that we have to pick and choose how much fidelity we apply to each system and each aircraft. How accurate the behavior is when we ship is mostly a factor of available time. If we shipped fewer aircraft we would undoubtedly have greater fidelity and probably higher accuracy as well. I think we do a great job with authenticity, but time is always a factor for that as well.
What we do with our aircraft is ensure that the systems are in place to provide a unique and characteristic experience which is appropriate for that aircraft. If it's a DC-3, we want the user to feel like they are in a DC-3 and not just a glorified 172. I think you experienced some of this with historic aircraft in FS 2004.
Although I can't give you specifics on what new systems we have developed, how far we have gone with fidelity or accuracy, or any real meat at all. I can say that we have made huge leaps forward from what you have come to expect from FS releases in the past, especially considering the number of aicraft we are producing right now. That said, our poor aircraft team is being stretched beyond their limits and stress levels are very high right now as we work toward our ship date.
Even as far back as a year ago, we were negotiating features and cutting functionality we didn't have time to tackle this time. Shipping a product is an ongoing balancing act and requires managing a set of compromises. That's a reality for any software product. The plus side is that what does get developed is developed very well and in a way that is extensible so all of your third party developers can create the awesome 99% fidelity aircraft they are known for.
Those features that end up on the cutting room floor are swept up and dusted off for the next version...