Why OpenOffice is not available in Ubuntu Software Center? If Ubuntu choose LibreOffice over OpenOffice, that does not mean that OpenOffice should be removed or not available as an option. Isn't having more options is one of the great things about Linux and Open Source.
If having problems coexisting with LibreOffice, a warning or a statement should be issued when installing OpenOffice from the Ubuntu Software Center, such as "You can't install OpenOffice and LibreOffice at the same time, would you like to remove LibreOffice?"
To be honest I'm having problems with LibreOffice such as it's slow and lagging when scrolling on huge pages of documents.