This is very much like borg technology it seems, though it lacks the green glow.
But actually this is a pretty nice prosumer device. I suspect that the entry level machine with 4 cores will be what Apple is keen to sell, I suspect the low end spec machine ( similar to current low spec on the Apple store) but probably a few hundred dollars cheaper. This will allow apple to sell more Apple Displays too. I actually think this is a clever strategy to get people who want to play high end graphics intense games. As far as expandability, I also think those days are over.
The daisy chaining ability would reduce the actual number of wires at the back too. Pretty sure there is some kind of tower of Thunderbolt external adapeter drives you can sit next to it. No doubt a third party will create a matching cylinder that you can slide other things into like SDDs graphics cards drives etc and only needing one cable into the main cylinder.