I don't have the new update yet and I have the more like already, so it won't be any different for me than before. That buy screen looks the same to me as even on my kindles when I go to the store. So also the same. Not sure why my thumb would be anywhere I don't put it though.
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But then I don't operate my phone with one hand, I am a hold in one hand, use index of other hand user. I can't operate a touch screen any other way. My thumb is the least likely of my digits to register touches and all my fingers are somewhat touch challenged. I think they are dry, not sure. In any case, I think I'll like the new look as its similar to what my kindles already look like and the app I currently have on my android.
As to the want to read shelf from goodreads, when they implemented the home view on the kindles, which can display the want to read stuff from the shelf, I moved everything I didn't own out of there and created a shelf called maybe to read. I put things I already own and want to read in the near future in the want-to-read shelf. Makes this integration work much better, since they don't let us pick our own shelf for that purpose.
Of course I am still waiting on this update.........