Supporting OOXML in LibreOffice

What happens if (as widely suspected) it is either impossible to write OOXML perfectly, or it turns out that Office only implements OOXML "pretty well"? In either case, Office is entrenched enough that the standard doesn't matter, and people will see LO as poorly implementing an Office format.

Fortunately, this means that "LO implements the spec perfectly and Office doesn't" is indistinguishable from "LO and Office both implement the spec imperfectly in different ways". (Well, in the absence of a major competitor that does do OOXML perfectly, but there isn't one.)