Well even the most rabid flight simulator enthusiast will agree that the simulator experience falls well short of reality, even for full mission simulators. The stress effects of sustained G cannot be reproduced, for one thing, even if some of the cues can be partly replicated.
As far as physics modelling is concerned the standard equations are well enough known, and modern PC have the processing power to do the number crunching at a sufficiently high frequency.
But I haven't yet seen a PC simulator of the sold in PC world etc category that acurratly reproduces the cockpit displays of the jet it purports to simulate. The display formats that are reproduced are just guessed at by the programmers and even if the programmers had access to accurate information they'd have to make compromises to reproduce minaturised displays on a single domestic screen.
Some years ago now, channel 4 I think did a 'recreation' of the Dambusters raid using PC technology, but without the control loads of an actual Lanc. At the end of it it was claimed that because a modern crew, with a female pilot had succesfully flown out all the training and the actual raid, it proved that a modern crew had the 'right stuff' to be a Dambuster. I think not, it took a lot of physical strength to fly a Lanc, and the PC simulation just didn't simulate control loading.