Some racket stringer in China actually did some educated guess on why the JS10 is plagued with sinking issue, and he believed that it had to do with Victor making the frame overly flexible. Historically, the most prominent sinking spots on the JS10 are the 5 o'clock and 7 o'clock positions, which also happens to be what Victor advertise as Nano-Fortify TR technology: Note: the above is not JS10, but the HX900 uses the same technology and suffer from sinking to a certain extent as well. As can be seen above, the tech was supposed to improve the 'elasticity and impact resistance' of the frame, which in layman terms should mean that the frame is able to bend more to increase repulsion and have better shock absorption. This could be where they got the formula wrong and these spots ended up being too 'elastic' (fragile) than it needs to be, which led to sinking issues. With the watermelon JS10 they tried to solve this issue by reducing elasticity, but not only did it not fix the problem (actually it did alleviate it somewhat on the 3U version) but it changed the playing feel where the racket now feels slightly head heavier and stiffer, which understandably are the side effects of making something more solid. That also explains why you feel more vibration, because the frame is now tougher. The ArcSaber 11 also falls victim to such sinking issue, albeit at a much lower degree. In order to maximize shuttle hold on the ArcSaber 11, Yonex made the frames too flexible (high frame flexibility = high shuttle hold, imagine the frame being 'sucked in' by the string bed on a powerful hit), and it led to a lot of frame sinking issues. These cases led me to believe that there is no way you can retain the playing feel of the racket, if you toughen up the frame you will always pay the cost of stiffer string bed, less flexibility and more vibration, unless there is a breakthrough in material. Of course, all of the above are just assumptions, so make of it what you will.