While iOS 5 is a great update over the current iOS 4.3.3, there are few features that should have been there but were left out due to some reason. I have been using the iOS 5 on my iPhone and here are the features that are missing compared to other mobile operating systems out there:
1. Widgets: Even after so much speculation, iOS 5 does not brings support for widgets. Widgets have been loved by the Android community and should have been there in the new iOS update
2. FaceTime over 3G: While there are unofficial ways of doing Facetime over 3G and 4G, iOS 5 should have allowed the users to do Facetime over 3G
3. Flash: iOS 5 still does not brings support for flash. Fortunately, there are still plenty of ways of getting Flash on iPad. (external link)
4. Voice to Text: Android has been doing this from quite sometime already now.
5. (Visible) File System: Users still do not have a visible file system to easily manage their files.
Read iOS 5 review (review was done by an iPad user)