4. Integrate Facebook
You've integrated Twitter, so why not integrate Facebook. Allow Facebook (as well as Twitter) updates from Siri, allow direct photo uploads, even allow us to share things we come upon while on the internet, or share our favorite song from the Music app. Think of all the possibilities that Facebook integration into iOS can bring!
This is down to Facebook, not Apple, it looked like all the code is there for it back in the beta for iOS5 along with the twitter integration, but just not enabled, FB prob wouldn't allow it, to understand why, just look at the Ping debacle
3. Make the Messages app an Aggregator
The New Messages app not only supports SMS and iMessage, but now you can get MSN, Yahoo, AIM, and Facebook chat right through messages. Each provider has it's own little icon so you never forget which service you're using. Windows Phone did it, so can you Apple!
SMS and Chat services like MSN/Yahoo, etc are, although appearing similar, totally different things. You might as well say to merge email as well at the rate you're going.
2. Data Management Utilities
Not everyone has unlimited data on their phone. Digging through to the "Usage" menu isn't convenient either. By adding easier access to see how much data you've consumed, you can help save people from going over. You can even add the option to warn when you're about to go over your data cap and set your monthly cycle so the iPhone or iPad easily knows when to reset for that month.
Carrier apps already have this. In the UK at least, on Orange, Three and O2, the apps show what data you've used and send you a free text when you're close to your limit and then when you've hit the limit.
My comments in bold