Phone Gap 1.6 fixes a bug with local storage that was caused by the recent iOS 5.1 update and resulted in SQL databases not being persistent.
“The inclusions of Cordova-JS paves the path for public plugin API and associated tooling."
The biggest change is the introduction of CommonJS style modules. This makes is possible to control your use of the API via a simple define and require type syntax. Some upgrading will be required to move from 1.5 to 1.6/
There is also some news about the future Cordova/PhoneGap 2.0. This will make any device API, be it core or specialized installable, discoverable and removable according to what the developer wants to do. The idea is based on the PhoneGap plugin idea.
All of these changes make working with different devices much more uniform which is, of course the whole point of the approach.