Don't show the attachments, or the 'Yesterday', 'Last Week' separators - these all waste space on the screen. I prefer to see more messages
First off, thanks for the feedback and for trying the new experience!
I just wanted to let you know that you are actually able to disable both the Date Separators and the Attachment Previews.
Click the gear in the top right and toggle off both of the settings.
Hope that helps