I'm not sure I'd want to switch to a pure UDP world just because there's lots of bandwidth in the data center. Any situation where Moore's Law works against you will run into problems unless there's back-pressure built into the protocol -- IE whenever you've got 100 clients talking to one aggregation point you'll get kicked in the teeth, regardless of if the endpoints are 100mb with the aggregation point being bonded 1gb links or the common media is 100gb and the aggregation point is ECMPed 400gb -- there are more of them than there is of you...

And -- building back-pressure into protocols is not trivial.... Getting it "for free" with TCP has been a net gain.