I see a lot of new offerings that have unlimited slow data. I doubt they regret it; it gives people peace of mind while still giving them incentive to upgrade.
Unlimited slow data is kind of cool. But unlimited, really slow, and free data (like the Kindle's Whispernet) is awesome. It's great to never actually be stuck completely without network access, even if you're somewhere your usual provider doesn't even exist.
I wish Google and Apple would copy the concept and just have their phones always be on the network, with cell plans just serving as a way to get voice service and get a decent download speed. Now that Google has built out an MVNO, they could definitely enable such a thing.