My memory of OpenDoc (and Microsoft's OLE) is that it was an effort to containerize software 'applets' and make them interoperable. Office software was huge at the time, and most of the demos were like "look how easy it is to add a spreadsheet to your word processing document." Live updates were big--make a change in your table and viola. That kind of stuff, and drag and drop, were cutting edge.

Microsoft and Apple had an arms race going where if one invested heavily in a technology, the other would follow to achieve some kind of parity. Video, productivity software, etc. I remember Apple leading a lot of these, and Microsoft occasionally embarrassing itself, like Quicktime/Video for Windows scandal, or when Apple released At Ease and Microsoft followed with Bob.

The long-term vision for Apple with OpenDoc probably involved commoditizing productivity software somehow to undermine Microsoft's market position. But it was technology with no proven consumer demand. And immature. Every demo I tried felt clunky, halfassed and confusing. But it was probably an attempt at recreating something from PARC (didn't Lisa have an Alto inspired document-centric model? I'm out of my depth when it comes to Xerox)