Previously, when connected to a 3G network, if you attempted to download an app the was over 20 MB, a popup would appear instructing you to connect to a Wi-Fi network in order to download. Now, that warning only appears when the app is over 50 MB -- which is a huge app; or, it used to be. Soon we'll be seeing Retina display iPad graphics included in universal apps, which could easily make even rather modest apps reach 50 - 60 MB.
Since the new iPad will be available with 4G LTE connectivity, the size increase makes perfect sense -- for LTE. Including 3G with the size increase is the cherry on top. Let's just hope it's enough. Those of us with capped data plans will just need to pay a little more attention to our monthly usage as app size increases.