It looks like it has timing pauses pretty often for when two heads are predicted to be too close, which makes having those wipers pretty essential. The flying Gantry style of the bigger machine cuts down how fast each head can move, but then that's not the point. I can only imagine how crazy this would be with a line of delta printers set edge to edge instead of Cartesian gantries.

As for dual extruders, it's only twice as many paths per layer per head, I don't see why it couldn't be done.