your gallery shows a lot of creativity and good composition. All very nice. I have a D7000 & D700 & D800. The D7000 would be a huge advance over the D90 you have and would enable you to extend your creativity (while using your current lenses). I think you are worrying too much about sharpness as that has almost nothing to do with your camera (lens and how you use the camera affect sharpness most). Your photos look pretty sharp to me. Explore the D7000 and you will find it has heaps of capabilities that you will be happy with.