Here's my very workable solution. I use a combination of iWork, Dropbox, and dropDAV, as follows....
Use a pointer to sync Dropbox with the Documents folder on the household iMac. This makes 100% of my files cloud accessible. There's the Dropbox app on the iPad obviously. But dropDAV is the key. It allows WebDAV access to Dropbox, which in turn means that it's relatively easy to get files in and out of iWork apps.
Bingo - a very workable file system.
Now obviously there is cost involved (extra storage for Dropbox. And dropDAV is a paid service). And some people have security concerns about dropDAV - and fair enough. But those are costs/risks I am willing to take in exchange for getting to use my iPad 100% of the time. (No I don't code, which the only thing you can't really do on an iPad these days; non-pro video and photo editing is readily available.)