I have many problems with email but I don't see how this solves any of them. How do I see who these were sent to, or what mailing lists they come from? What do the chevron and gear icons do? How does it scroll when I have more than 4 emails? How does search work? How does composing work when I have more than one draft in progress? Does it just ignore my folders/flags/accounts? How do I move/minimize/etc these views if they don't have normal window frames?

This is the danger of judging any design by Lorem Ipsum. If it's not using real data, I don't trust it to be a real design.

JWZ said in 1998, "Mozilla is big because your needs are big. Your needs are big because the Internet is big. There are lots of small, lean web browsers out there that, incidentally, do almost nothing useful."

The standard window frame controls are not a problem to me. In fact, my #1 gripe with every program that tried to customize them (e.g., Pixelmator, Affinity, Firefox, 1Password) is that they screwed it up somehow and everything would be better if they'd just used standard controls.