I always thought more people would migrate from MS Office to OpenOffice to *avoid* the Ribbon and stick with a more familiar UI.
I say this as an OpenOffice user of many years, and as someone who has never used this fancy new Ribbon business in more recent versions of MS Office. The Ribbon in MS Office is one feature that helps keeps me in OpenOffice, and keeps me from upgrading the old version of MS Office that I have hanging around just in case I need it.
Ideally, both old and new interfaces would be available, and could be selected in the Options. In reality, this probably puts a lot more load on the developers to maintain two quite different interfaces ....