The apple display needs to be upgraded to properly complement this device. If it could power up the MacBook while also serving as a thunderbolt (for other machines), usb3 and yes, FireWire hub with a 5k screen, who here wouldn't buy one? A single cable will do all.
Post spec: could this thing run a 5k external?
Further speculation: Realistically the display would have HDMI, Ethernet, two thunderbolt, two USB 3 and four USB C.
This would also be the ports in next iMac.