People interested in UK scenery for FS2002 might be interested in this link:
http://www.uk2000scenery.com/puplic/index.htm There's UK scenery and UK airports. I would imagine that any of the scenery is more accurate than the out-of-the-box MS stuff. The problem is that you might need a beefy PC to run it on to get decent framerates, but worth looking at the demo perhaps.
Concerning aircraft and flight models, you may want to look at the file libraries avsim.com and flightsim.com. There are a few really good general aviation free add-ons out there with vastly superior flight models to the standard MS ones. There's a really nice DC-3 out there too, and sadly flight sim is probably the closest I'll get to flying one of those. For jets,
www.projectopensky.com, www.phoenix-simulation.co.uk and
www.dreamfleet2000.com are all good sources. The last two cost money but have new panels and attempt systems simulation. As a private pilot, I'd be really interested to know how "good" these airliner models are from real drivers.
Remember that everything has to be done within the constraints of the flight modeling of FS2002 so I would imagine that some things just aren't possible.
Finally, I'm hoping we'll see some nice add-ons once MS releases the developer's kit for FS2002. I'd love to see improved ATC for example.