While it's possible the Razr HD won't be released until Verizon forces new contracts to tiered data I think it's pretty clear that the release of the first Apple LTE phone is driving this bus.
My bet is Verizon has millions of customers with Apple phones that have grandfathered unlimited data plans and Verizon fears what will happen to their network if all of those customers upgrade to an Apple LTE phone and start consuming massive amounts of data.