My initial reaction is DO NOT WANT!
So long as I dont have to use the iOS features thats fine. If I wanted that I'd use my ipod touch. When I'm on a desktop computer, I want to use it as a desktop and not an oversized ipad, which itself is just an oversized ipod touch.
What scares me is the possibility of the app store becoming the ONLY source of third party apps. I think the mac has been too long for that to happen, but its still not outside the realm of possibility.
This new update will be Identical to 10.6 with added features. Like a Home Screen that can be enabled via a Hot Key allowing a "Splash Screen" of most used applications.
10.7 will still run and act like 10.6 but with added features resembling the iOS UI