The design of the icons will not change and we are not likely to see widgets appear on the OS, but the redesign of every icon has been focused on and the OS is more stark and minimalist than previous versions.
A leaked image of the Calendar app and others showed us how this design aesthetic would be placed within the apps. We believe while functionality on iOS7 will remain the same, there will be a full redesign.
We will have to wait a few hours for the press reveal by Apple. We hope Jony Ive will appear to discuss iOS7, considering he has had a major part to play in the development, but he is rather shy when it comes to these conferences.