I'm not sure what you mean. iWork documents are synced, but it has to be done manually through the browser on the Mac side.
As soon as you open on your iOS device a document made on iWork on OS X that has features that are not supported on iWork iOS, those features are immediately stripped away from the document on the iCloud servers. Here is an example.
Create a document on your computer in pages, and call it iCloud test. Type a few sentences. Then add a comment to the file. Then upload that file to iCloud through your web browser (Safari). So far everything seems to be looking good, and it looks like the file was synced to iCloud. But the moment you open that file on any iOS device, you will get an error that Pages does not support comments and therefore they were removed. The program, pages, on your iOS device, will now upload a new copy of the document to iCloud, replacing the old one with the new, stripped down, version. If you later downloaded that file back to your computer, the original comments would be permanently gone or lost. Imagine if all your documents were automatically uploaded to the cloud and synced back to your computer when changes are made on the iOS device, well then all those extra features would be eliminated from all your files any time you open them up on an iOS device. In other words, if auto-sync was implemented, that would mean reducing iWork on OS X to the features, and only the features, that iWork on iOS can accomplish. But as Apple itself recognizes, the porting of iWork to iOS is only begun and very limited.
Naturally, features, like comments (and there are many many others), were added to the desktop version of iWork for a specific reason. They are needed and often relied upon. For a fully functional and acceptable iCloud environment the type of problem I just explained needs to be removed by making sure each suite, for iOS and OS X, can accomplish all the same tasks.
