Once again, this is already the case AFAIK. At the very least, publisher and visio support is implemented using libraries that are not directly tied to LO.I hope LibreOffice splits the format support into a modular library thing, so all Office Suites/Text Editors/Viewers could use the same code for reading/writing. This could make possible that other projects could be more interested about contributing in better supporting those formats, providing fixes or better support of those (or even new supported formats).
I dunno, I had to keep Apache Open Office 3.4 around with LibreOffice 4, as LibreOffice (at least for me) seems to have regressed quite a bit in their Word/PowerPoint filters. I have a few of both that get horribly currupted in LO, but AOO open them fine.
Seems rather a waste to have both Apache OpenOffice and LibreOffice.
It would be nice if they could be merged back to one again.
However, every single modification to to that code is licensed under MPL.
If any other FOSS project acted that way, it would be at least considered rude to make modifications to a forked file under a different license than the original. It may even be considered hostile.
So far I didn't see any hostility of Apache's OO team against LO, only the other way around. A few months ago Document Foundation members accused Apache of lying, claiming that no Symphony code was ever donated to Apache by IBM. Yet, LO 4.1 now has that “non-existing Symphony sidebar code”.
Personally, I have more sympathy for Apache because of these actions by TDF.
Technology-wise, though, both projects are rotting meat. Both projects still use VCL and both projects still run in a single monolithic process. Calligra has the superior architecture. Sadly few people realize that which is why Calligra lacks a bit of robustness a handful of additional bug-squashing contributors could remedy…