We convert the document to a third party format (like pdf) on upload and retain a copy of the original on the server. It is very difficult to handle all the embedded information in a word document For example an embedded excel table. We also use a simple method of embedded markers so that if the document is distributable and the device has a native APP associated to that document type. The user has an option to read the document in the native format. Anyway, a few suggestions... all of them pretty easy to implement.
All word documents are exportable, it is a matter of training your users when they save the document.