I think if he doesn't take to the new racket, it might have him second guessing himself. Plus, if he doesn't commit to a schedule that makes him play, but instead tries to get by on the minimum commitment, he'll find it hard to get up to speed for big matches. As it is now, he's not even falling in the big matches - he's falling before them.
I expect him to commit and come out charging. Whether it'll have an effect or not, we won't know until next year. He's not going through Rafa in a slam, and maybe not Djoker or Murray either. The makeweights are throwing shapes, so he'll be dragged into more brawls there too.
I think next year he may have to work hard just to stay still. This is normal - he'll be 33 next August!