Both Verizon and AT&T have made it clear that they want to ditch the current (sort of flat rate) wireless pricing system to one that involves more caps and per-byte overages. That's (and sorry to repeat ourselves) because carriers want to prepare for the inevitable revenue losses they'll see as mobile VoIP and push IM clients begin to erode voice and SMS revenues. The carriers pitch these changes as being about fairness and even altruism, and it works.
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Neither AT&T and Verizon have officially announced LTE pricing, in part because they're curious to see what kind of pricing consumers will tolerate. If you tell them that low caps and high overages are a good value by buying their service, guess what kind of pricing model you're going to get? Consumers are going to have to pay close attention and ask lots of questions (will my unused gigabytes roll over?) as the wireless data pricing of tomorrow gets hashed out.