Yeah, and for those of us that are grandfathered into unlimited data, we'd lose our unlimited contract while upgrading. I'll stick with my 4S so I don't get squeezed per gig.
Verizon makes it easy to increase your monthly data allowance for a month as long as you request it before the billing period is over. It automatically reverts back to your base plan for the next month.
They even send you an SMS as you approach your limit. It's as simple as a call or chat through their terrible website requesting a one month increase.