I think we need to reserve judgment on the UI until we actually see it.
One thing is clear, it will be a lot different then what we are used to seeing, it will tick off some users and Ives has a great track record for design.
Exactly, the team behind Ive's is the same as before and they will help guide him, and Ive's is smart enough to know software isn't hardware, it needs to be functional as well as stunning. With him in charge I think we are going to be in for a treat and we will see something evolutionary, it'll look different but I'm also hoping for a lot of new touches but with Apple flair, like these mock ups of widgets we've seen.
On a side note I'm wondering if iOS7 will be flatter then Android 4.2? it's flatter then iOS 6 is but will Apple be even flatter?