If I had to take some wild predictions/hopes, I'd say:

  - The Thunderbolt Display live on with the iMac, the new iMac having
    a new Thunderbolt target mode, allowing USB-C Macbooks to use all
    its peripherals/ports, including the GPU.
  - This new iMac will also be released with a touchbar keyboard
    accessory
  - e-ink keys keyboard will either be released with the new iMac or at
    a later stage, also triggering an update on Macbooks, which, as a
    side effect, will allow Apple to reduce its number of SKUs
  - no new Mac Mini, the iPhone has now enough power to take over that
    role with a new accessory or target mode and code updates on OS X
    allowing everyone with an iPhone to try or use OS X
  - Mac Pro will be updated

In short:

  (1) the thunderbolt display will merge with the iMac
  (2) the Mac Mini will merge with the iPhone