Just think of what could happen when those flood gates are opened with all the data today's phones can burn through. Streaming movies and music for hours on end, using torrent apps, etc. It would start clogging the networks, slowing speeds down, interrupting data service all together, and maybe even disrupt actual phone call service because the carriers don't have the network capacity for all that traffic. From my understanding, that's one of the big reasons the caps were put in place to begin with. You think data plans are expensive now, just let government force unlimited plans and watch the price skyrocket do to the rapid need to increase infrastructure and capacity!
I think unlimited would be awesome to have again, but not by government force. Besides, I'm plenty happy with Verizon.