Features not included in FSX...

FMS, ATC, SIDS & STARS were all considered but were dropped from thought due to the following...

All of these features are often requested and we are very aware that one segment of our users want these in the product.

We seriously talked about all of these during the development of FSX and there were several reasons why each fell off the plate.

FMS - I designed a pseudo FMS using the GPS backend that might have worked okay, but in retrospect the people that really want an FMS would have been disappointed with it and the majority of users wouldn't have cared, so it's just as well we didn't pursue that design.

For an accurate FMS, we would have to build a different one for each of the jets in our fleet, modify/upgrade the flight planner system, and incure the testing time penality to get it all done.

Instead of the FMS, we decided we should get a little closer to the current buzz in GA and do the G1000 which we think will appeal to a wider audience. We could not have done the G1000 if we had tried to provide FMS functionality in our jets.

We may decided to build an FMS or two in the future, but for now, the third party community is doing a great job with this.

SIDS & STARS - The same arguments described for the FMS apply, although it mostly comes down to a lot more data that I'm not sure our contracts with data providers includes (it may, I'm not sure), a huge testing load to see if they all work, and without the FMS, it wouldn't make a lot of sense to have them in the first place.

ATC Enhancements - This seems to have the most people tied in knots on forums, and I think it's understandable that they are. During the initial design and redesign for FSX, all of the various requests for ATC were on the table. Many of the fixes are more complex than you would think, and are risky because we could easily introduce more bugs and problems in the end. That said, I'm sure our developers are capable of doing most of what has been requested, but not easily. For instance one of the requests is to make the voice speak faster and more realistically. Frankly, using the system we have that will NEVER happen. We have thousands of lines recorded and these are combined as you fly to build the phrases necessary. To do this takes time and it will never sound natural.

The ATC system is labor intensive and with every version of the product we need to record more lines. To support international accents would be virtually impossible for us to do as we would have to record thousands of lines for each accent and the accents might get messed up because of how we combine different lines to build the resulting lines you hear. On top of that there are storage space concerns for each accent, so we would probably have to limit the number of accents we could do, and then we would be criticised for not including this accent or that for a particular region of the world. It's just not worth it...

As for the future of the ATC feature, I have to question how long we should carry it along. The long range future of the franchise will be on-line and getting the ATC system to work on line is a nightmare concept. I am all for retaining a single player experience into the future, so maybe it will continue to be maintained going forward, but it will be a little unlikely that we will invest a lot of time and money expanding the system further (I can hear the cries of unfair treatment and M$ commentary already).

As for the on-line element, I really think it's more fun, more interesting, and potentially more realistic to interact with a real human controller than to use our ATC system. VATSIM is hardcore and intimidating for most users, and frankly requires either real pilot training, or at least some study time before a user would be accepted within that environment. We built our Air Traffic Controller options in multi-player so that users could have this experience in smaller and hopefully friendly sessions and try it out with a real human controller. If you don't like one session and a particular controller(s), then join a different session. We hope to promote controllers that can build a reputation as great controllers to interact with, and kind of make them celebrities in their own right. Maybe we will just have our community team play that role until it all gets going on it's own.

Eventually some of our users that cut their teeth on smaller sessions will try out VATSIM or IVAO or some of the smaller MMO groups and grow their skills that way (it should be technically much easier to get into these groups with FSX).

From http://blogs.technet.com/p-12c_pilot/archive/2006/08/24/449488.aspx