Nikon has now officially unveiled the D7100 which will succeed (but not replace) the D7000 DSLR. The main improvements are in the areas of sensor resolution and the number of autofocus points. The film mode has also been improved, and the low-pass filter has been removed from the sensor.
Despite what some were secretly hoping in the run-up to the Nikon announcement, it's not a successor of the D300S, but an upgrade of the D7000. The interface has remained intact for the most part. The size of the sensor is 1.5x crop DX. Nikon is positioning the D7100 between the D7000 and the D600, so the D7000 will remain available.
The sensor has a resolution of 24.1 megapixels and Nikon claims it's not the same sensor as in the D3200 or the D5200. While the ISO range has remained the same (100 - 6400), Nikon says it has been improved in quality compared to the D7000. The Hi 1 and Hi 2 settings are also present.
The low-pass filter on the sensor has been removed, which was also done with the D800E. This filter removes moiré, an interference pattern created, for example, when two grids are overlaid at an angle, or when they have slightly different mesh. The drawback of such a filter is that you lose some detail. This means that the D7100 should be able to take sharper images, and Nikon indicates that the higher resolution causes moiré to be barely visible even without the filter. Moiré can be removed with software as well.