Why I think MacPros need Thunderbolt. (especially if you use a MBP)
#1 – Pegasus enclosures. I maybe wrong, is there anything else on the market that give 12TB with Raid 5 @ ~800MBps speed for 2 grand. (I have not priced SAS in a while so they maybe getting close.
#2 When (if) more small-fast TB drives come out and used on the field you will need TB on your desktop system.
#3 New Apple monitors, which also give you another hub, but the hub is not that big of a deal for MacPro.
#4 Ability to use one video device on desktop or Laptop.
#5 It will give Apple an open door to reduce the PCI slots and form factor in MacPros. (this is an opinion)
I think TB is a given, it is a good thing and if they can put it into a MacMini it not hard to roll it into a MacPro price wise but I agree it is a much bigger deal for the MBP and iMac products.