That padding is one of the only issues I have with the new layout. They should have left an option with the classic padding.
When he selects "compact", it looks like the classic padding to me.
I'll watch the video when I get home, but Google is having a love affair with white space on this new layout, I'm doubtful about the padding on the email list.
I just switched to the new look and (after changing the density to "Compact") I could not notice a difference on the padding.
It was a nice surprise.
Are you working on anything related to this design?