Indeed, the XZ has a lot in common with the Z5. The display, for one, is the same size and resolution as the last generation - not necessarily a bad thing, but the XZ also comes with 3GB of RAM - modern-day flagships will crack a condescending smile seeing that in the spec sheet.
No one will laugh at the rest of it, though - top-of-the-line Snapdragon 820 chipset, 23MP camera with a trio of focusing technologies and 4K video recording(one could think the Z is required for that, had it not been for the M5), high-res 13MP front camera, Type-C connectivity, fingerprint reader, IP68 rating, stereo speakers - name one thing missing.