If you REALLY miss the "old" transparent tiles from W8.1, you can get it by restoring the Insider device from an 8.1 backup. It will install your old apps, and set up the background up like on W8.1 but will still keep W10
Downside is, if you change to background from settings after this, it will use the new kind of background.
Since it's clearly technically possible for W10 to do this kind of start screen, it's strange that there isn't just an option for it...

Downside is, if you change to background from settings after this, it will use the new kind of background.
Since it's clearly technically possible for W10 to do this kind of start screen, it's strange that there isn't just an option for it...