Is a person fully able to make use of iCloud's ability to store and sync documents in the cloud if a person is not a die-hard iWork user? I see that if I use Preview.app its new method to move files to the cloud, I am not able to access it on my iPad or iPod.

I have only one Mac, and an iPad and iPod touch. I use MS Word, Excel, etc., not iWork.

Given the above, am I right that iCloud does not really serve me, with regards to hoping to shift some of my documents and work into the cloud, for nicely synced access and consumption on other devices?

(Note, I understand that iCloud's features syncing calendars and contacts work fine. I am talking about documents syncing and cloud storage features -- whether they do not serve my situation.)
If you don't use iWork, iCloud will not help you very much for your documents and other files. On an iOS device, you can only open iWork files from iCloud. If you use any other file types, Dropbox would probably be the best alternative to iCloud.

Although Mountain Lion allows you to store other kinds of files on iCloud, the only benefit you get from that is cloud backup of those files. However, if you want more than 5 GB of space, you have to pay for it, so it's likely not worth it.

Update: I read that app developers now have the ability use iCloud to store files used by their apps. So, in the future, Microsoft could allow for you to have an iCloud library for MS Word files so that you could save them to iCloud on your Mac and then open them in your Microsoft Word application on your iPad (which doesn't exist). The catch is that the developer has to make the Mac app and the iOS app for this to be possible. So, as a counterexample, since Apple does not have a TextEdit app for the iPad, you can't open TextEdit files from iCloud on the iPad. Some company, though, could write a Mac app and an iOS app that allows you to edit text files from iCloud on any device.