Since the D5200 has not been introduced yet, it is impossible to provide a reliable answer to your question. If the rumors are correct, the D5100 will have more resolution and Dynamic Range than the D7000. The D7000 will have a Better AF system, Sub-Command dial and dedicated buttons to quickly change settings without going into the camera menu. It also has a penta-prism viewfinder which is much brighter than the penta-mirror viewfinders on the D3_00 and D5_00 series bodies.
If they are not in a hurry to upgrade, the D7100 and or the D400 (maybe) should be in the pipeline in the near future. Both should have the same or an improved sensor as the D5200 in a more robust body. Good Luck and Enjoy your Nikons!