I don't think that you can break circuit design down into a mathematical equation that, if followed correctly, will always produce good racing every single time. And if you could, well, we'd probably end up with twenty identical circuits. I believe that a good circuit is one that is more than the sum of its parts, and that a holistic approach is needed. The approach to each turn will simultaneously influence the approach to every other turn.
If anything, the exacting regulations with regards to surfacing are perhaps the most to blame. When China joined the calendar in 2004, it took a lot of criticism for being bland and uninspiring. However, the past few races there have been very good, and I believe that this is because the circuit has had time to age. The surface has settled, the weight of the buildings has put constant pressure on the topography, and the earth has natraully expanded and contracted with the passnig of seasons. The end result is that the surface is no longer as smooth as a billiards table. While there are still complaints about Shanghai, they mostly have to do with the number of people in the stands or the quality of the air around the circuit rather than the actual racing.