One cable that leads to a brick with a million cables. That's a more cluttered desktop work area.
Not if the hub is tucked behind or below your monitor and the "million cables" emerge from the back of the dock rather than from the side of your laptop.
But just to mirror the existing ports on another box seems useless to me.
TB docks don't just "mirror" the existing ports: they give you extra ports and leave the ports on your laptop free. So, e.g. you get 3 USB3 ports on your dock to plug in you printer, scanner & backup drive leaving the 2 existing ports on your laptop for things you want up-front, like USB memory sticks - and the USB ports on TB docks are "1st class" ports with their own controller, not shared ports on a USB hub.
Plus, most TB hubs do give you new types of port: most have Ethernet (which doesn't feature on any rMBP or Air) the Belkin one has FireWire, Akitio has eSATA, many have HDMI (doesn't feature on Airs or 2011 MBPs) and they'll all add USB3 to 2011 MBPs.
I agree that the USB provision is a bit mean: I guess that they're using a 4-port USB3 controller and taking one port for sound. To give more ports they'd probably have to integrate a hub, which would mean sacrificing a "1st class" USB3 port to drive the hub. ISTR that Windows (spit) has a borked Thunderbolt implementation that limits the number of controllers they can include (at least, that was one of the reasons given for the non-appearance of the Sonnet dock).
Pity about the Sonnet dock - 4xUSB *and* FireWire *and* eSATA *and* digital sound *and* ethernet *and* internal hard drive *and* internal optical drive would really improve interface diversity and start to cut through desktop clutter. If only they could actually get it on the market...
