It seems the Chinese have a little different perspective on "air combat maneuvering". One of the reasons Red Flag and Top-Gun came to the fore was to "ingrain" this type of flying into the curriculum in order to bring people up to a high level of "airmanship", where aircraft maneuvering was second nature.
Well, I don't think you can speculate about the "airmanship" based on what is happening with the J-20. Most of the photos / videos that we have seen with the J-20 so far have come from the prototypes flying in Chengdu. Now, Chengdu is a highly populated city, in fact one of the most populated cities in China with 12-13 million people. In almost all the photos with the J-20 in the air, you can see apartment buildings nearby. I don't think it is safe to make any of the aerobatic maneuvers in the sky above a major city over a densely populated area even with a mature plane, much less a prototype. the same reason that we used to see F-16's and F-18's flying by all the time when I lived in College Station, Texas, but never saw any of them making any kind of cool maneuvers... they do those exercises in the desert in the west Texas...
Secondly, IMHO, the PLA wants to keep what the J-20 can actually do a secret. So it makes sense that they don't want to expose any of the advanced capabilities in a place where it can be seen and photographed so easily.
So with that said, if someone can go to Yanliang, he / she might be able to see the J-20 making all kinds of awesome maneuvers, assuming that they can take a photo. However, I do believe that the security at Yanliang might be a lot tighter than at Chengdu.