iOS 7 comes in the age of Facebook Home and Jelly Bean, not BlackBerry OS 5, or Windows Phone 6. The game has changed. And while Apple has undoubtedly pushed its mobile operating system forward over the last few years, it hasn't done so without a few missteps, or missed opportunities; plenty of criticisms surround iCloud, Maps, and Siri.
There are a ton of things that could be updated, and
expanded, in the next version of iOS. But I've condensed such a list to just 6 Items. Here they are:
1. Siri APIs
The capabilities of 3rd party apps should be accessible through Siri. The model already exists, but it’s limited to the Apple Store app. Imagine if you could reply to a Facebook message, or add an item to your Wunderlist, with the convenience of Siri.

Another aspect of Siri is databases. Currently, Siri has a limited range of databases that it uses for information gathering, or directly accessing content. By saying “Play the latest episode of Boardwalk Empire on HBO GO” or “What is the App Store’s ‘App of the Week’?” you could access content on iOS with ease. The same would also be the case for apps that really have huge databases of information. Urban Dictionary, Google’s Translate app, or the UN’s CountryStats app, just to name a few. In the future, there could even be a way to simply download databases, or access to databases, without an app.
2. Core App Replacement
Apps like Mailbox and Google Maps are great alternatives to iOS’s core apps. In fact, Google has built alternatives to a lot of core apps. But there is no way, on a system level, to replace stock apps with a 3rd party alternative. I think that iOS 7 should have some of the flexibility of its desktop counterpart, OS X.

But it could still be strict if it wanted to. If a developer wanted to submit an app to the App Store that could replace 1st party apps, it would have to stand against slightly higher standards. That’s because core apps carry out core functions. For instance, if you want to make a mail app replacement, you would need to also make an in-app mailing UI that other apps plug into.
3. Open Action Sheet
iOS apps can handle different kinds of content. Instapaper can handle articles from the web, Instagram can handle images, and Twitter can handle short lines of text. So why is it that when you tap the action sheet button in Photos, there isn’t an option to share it on Instagram or Tumblr?

It’s more than the simple “Open in…” that you might see in the mail app every now and then, because the action sheet is about opening something in order to commit a specific action (not just storage). That means that you could press the action sheet button in Safari and DM the link in Twitter or Tweet the link in Twitter. Two actions, one app.
You could customize the sheet in the same way that you can customize the home screen, but removing item from the sheet would have to be done in settings.
4. Improved Account Management
Single sign-on for Twitter and Facebook was a great addition for iOS. But it should be more open than that. Apps should be able to tell iOS that there is an account associated with their app. You would only need to sign into the account once, and you could give apps privileges by simply tapping “continue.” Tumblr, LinkedIn, Google and Microsoft are great examples of accounts that could really benefit from this kind of openness.

You could manage the accounts through Settings. You would also be able to add Exchange accounts in that same menu.
5. Intelligent Icons
Icons should be more dynamic. Since iOS 1.0, the Calendar app has shown the current day of the week and month. Weather on the other hand has been telling users that it’s 73 degrees and sunny for half a decade. Apps like Music could have an equalizer for the current song subtly bouncing behind the music note. The Phone icon could pulse a glowing green when you're on a call.
6. 3rd Party Widgets
Apple was so close to making a lot of people happy when it made widgets a part of the Notification Center in iOS 5. But because they only let users see weather, stocks, and social media sharing buttons, users continued to demand widgets. Any iOS app developer should be able to build a widget for the notification center that displays information relevant to their app.

Widgets wouldn't really be interactive, besides simple swiping. They would just be informative. Tapping the widget would open up the connected app.
3rd party apps need to become 1st class citizens. If Apple wants to find success by making users happy, they need to allow users to decide how they send emails, share pictures, and interact with the world around them. Apple’s stock apps have only gotten us so far, and Apple can only make Siri do so many things before the software gets bloated functionality. By allowing apps to plug into core iOS functionality, Apple would be developing an OS that could be both powerful and simple. And it might win them a few battles against Android.