There is one thing I really wish iCloud would keep: iDisk. Aside from mail, contacts and calendars, that was THE most useful feature of MobileMe, and it's going away with it.
Documents in the Cloud just isn't the same thing. Oh I can save my iWork files in the cloud? Great. But what about MS Office files, application data, XML files, camera raw images, the web development projects I need to transfer from system to system, and all the other "big boy" computing stuff that keeps me using a desktop and laptop?
I'll have to switch to dropbox in June, and I'm planning on it, but I wish I didn't have to. It's not QUITE as good as iDisk has been. And while iCloud is free, I'm still paying $99 a year to keep functionality I need, it's just going to some other company that might not be quite as stable financially as Apple is.
Other than that, iCloud I've found quite useful.
To the OP: best thing to do is to list all of the things you don't like about iCloud and all the things you wish it still had from MobileMe, and e-mail Tim Cook about it. I did. Apple needs to hear feedback from people who were paying customers of Mobile Me, and might still pay for those features we've grown used to if they're made available as a premium add-on or something.