For basic camera functions, the specs do tell a story of a camera with higher resolution, lower noise, a more sophisticated metering system, and if following the legacy of the D90 higher base ISO DR.....to me adds up to a camera that greatly exceeds the D90 which has essentially the same IS, although wider DR, than the D300. So concluding the IQ superiority of the D7000 over the D300 is not an extravagant claim, it would be the most conservative claim.
My own playing with the D300s belonging to a friend, who shoots in some of the same venues I do, is that the only point that his shooting was positively enhanced over mine was the AF system was faster and was more accurate on the outer focus points. I always used the center cross-polarized point since it worked so much better in the dark environments. If he missed a shot it was do to pilot error, if I missed a shot is was pilot and or possibly recomposing from the lock on of the center point, resulted in oof. But otherwise they were both close and we both got 50% more in focus, properly exposed images than our friends who use 7d and 5dII in the same venues. They had a poorer result because of unpredictable focus in low light despite having a lot more experience.
All these issues considered, the fact remains that what camera was used is still and will always be the least important element in determining if a photo is compelling, interesting and communicates. Way too much emphasis is placed on new models and specs primarily because all else is hard to quantify, measure or rank. As with most hobbies most people focus on the trappings of the hobby, the lore, traditions, equipment, individual specs instead of actually doing the hobby. I find myself somewhere in the middle ground, the tech stuff is fascinating, the engineer in me, but I also get caught up in shooting massive amounts, 400-600 a night and at the end of the night guessing the 6-7 hours was over in a flash, and assuming 80 shots where made....
I've a number of hobbies where the equipment is the prime interest to me. When I got into flying I discovered I tinker with, repair, rebuild my plane more than actually fly it. Same with Amateur "Ham" radio, I was passionate about it as a kid, and learned all I could about electronics from age 10 because it was related. I found I was mostly fascinated later on by experimenting, designing and building gear and spending little time actually using it. And high quality audio systems, I design, build and tweak all sorts of exotic audio gear yet do not even own a sound system to listen to anything. Photography is one that is the most balanced for me, liking gear but also get all wrapped up in lots of experimenting and shooting where time stands still and I forget that I had an appointment or that I was out shooting for 10 hours but planned on 2. The D7000 is very very exciting to me but it would not change any of my subjects(well, maybe more available light), or results. Mostly I like to shoot people, and having a connection with them, like those in the gallery, all personal friends, is a real joy. Stan St Petersburg Russia