I'm not impressed with this device either, unless you really need a one-cable connection to your desktop devices (keyboard, mouse, storage, network, display). I also don't understand why they put the USB 3 port on the front of the dock (why not on the back with the other data ports?).
However, for those asking for more USB 3 ports I doubt that would be very practical since the sustained data rate on those ports would likely have to be lower than the USB 3 maximum (i.e. you couldn't have two USB 3 drives connected to the dock and expect concurrent access at true SuperSpeed, USB 3 date rates).
USB 3 offers 5Gbps while Thunderbolt does dual channel 10Gbps. However, once you connect a display to this dock you'd already be well on your way to using up one of the two Thunderbolt channels (in fact, I think -- but am not sure -- that video has to run over a dedicated Thunderbolt channel, thus on a single channel you can't multiplex video with anything else). That would leave one 10Gbps Thunderbolt channel for everything else and thus having even two UBS 3 ports would mean you'd be at the end of the available bandwidth.
But, even if you could multiplex the video with other data (on a single Thunderbolt channel, which I admit may be possible) you'd still be pretty close to the bandwidth limit of a single Thunderbolt PORT once you had more than two USB 3 SuperSpeed devices connected to the dock (assuming the need for a video connection). I suspect that Matrox is just being a little conservative (safe?) by offering only a single USB 3 port, two might be possible but it would probably be running right up against the theoretical maximum for Thunderbolt (once you include everything else, display, ethernet, audio, and the two USB 2 ports).
