The problem with FS2K was that it relied heavily on the CPU for it's 3D rendering, which is totally stupid. I replaced my old Savage 3D card with a Geforce2MX card and got maybe a 5% increase in performance.
FS2002 will apparently use the Combat Flight Sim 3rd generation rendering engine which uses the 3D accelerator card MUCH more.
Result will most likely be that on the same computer, FS2002 will perform much better than FS2K.
Think about it, the 3D environments in FS2K are not that intensive. Take a look at a game like Alice that has stunning 3D environments and works extremely smooth in the highest resolution on my machine.