I think I like Sony's approach to Thunderbolt better.
I mean, why extra cables? if I can use one single cable type (USB3/TB compatible) throughout devices, that's the standard I would pick.
By going with mini DP, we basically have to add one more type of cable while using USB devices.
If USB-IF really worked out a deal with Sony to use USB3 ports as TB port... please Apple, just follow it. I don't want your TB to go the way FW800 has gone. I don't mind having a little adapter to adapt from current miniDP form to USB form...
Perhaps this was the reason why all the announced TB products are having non-firm release date?
Rather bad arguement, a TB cable would have different wiring than USB 3... in the case of Sony's implimentation, you would still need a different type of cable... now you'd be stuck with several cables that look similar but aren't and figuring out where the cable is for the right device.
Also, who wants to waste their only available TB port with a USB 1.1 device? I'd say leave Thunderbolt ports seperate from USB. They have different, non-competing uses.