Shipping this weekend besides Debian 8.7 is the first release candidate of the Debian Installer for Stretch.
With this release it does switch away from a merged /usr as the default setting for debootstrap. They were hoping for a merged /usr for Debian 9.0 but that isn't going to happen now for Stretch due to open bugs around it. More details on the "Usr Merge" can be found via this Debian Wiki page.
Updated in this Debian Installer release include moving to the Linux 4.8 kernel, some font changes, improved /etc/network/interfaces handling, ARM hardware support updates, and various other changes.
More details on the Debian Installer Stretch RC1 release via this mailing list announcement.