I'll leave with one more idea, just in case a full on merger doesn't work out, and that's what I'll call a soft merger. If a goal of modularity is pursued, there may be room for collaboration on shared components across projects. For example, the libraries for reading and writing to proprietary formats would be good candidates to be developed as modules, which could have benefits for more than just office suites. Just something to consider.
So it's not like there aren't already chances for the integration you propose, that span a broader section of the FOSS landscape than just LO/AOO. But ... You'll see that Document Liberation is spearheaded by LO/TDF and ignored by AOO/ASF.
Sorry, but that is incorrect. There is the Incubating ODF toolkit at Apache for example. Now it is true, of course, that the TDF is focused on ODF (in other words, that is it's stated goal), but Apache is hardly ignoring it. The mission statements of Apache and TDF are wildly different, but characterizing something as being "ignored" simply shows an ignorance on how the ASF operates.
In the mean-time, MS Office isn't even part of my consciousness. But I'm a pretty rabid FOSS ideologue who has used Linux and FOSS office suites as his primary desktop environment since about 2002. So I'm a little out of the mainstream, you could say...