The OpenOffice.org-project has proposed a “ODF Toolkit” which is intended to become a framework for creating and modifying ODF documents. Compared to a fully fledged Office application the toolkit is supposed to only deal with the pure modification and creation of ODF files. So there will be no GUI, no stuff around like an embedded spell checking, and so on.
Also, and there you see the strong roots in the OpenOffice.org community, the new framework is supposed to have a clean API, designed exactly for that purpose. In contrast, OOo already existed before ODF and was somehow ported to the new standard.
The long term aim is to port OOo to that framework too, once it is created and proven.
The advantages are obvious: first of all, everyone could concentrate on their tasks: the framework developers would concentrate on their framework, the OOo developers would concentrate on making OOo a usable GUI and a shiny app. Also, other projects could take advantage of the framework: if the aim will be reached that it becomes easier to handle ODFs with that framework other applications could add ODF support quicker and easier – more apps would arise.
Also, imagine someone building an entirely new Office suite on top of that framework – the developer would “only” have to focus on the GUI and the integration of the framework.
Also, since it is supposed to be developed without a GUI, there could be server side services developed around it. Especially a conversion application would be nice: if there would be that framework for central development of converting ODF to other file formats the quality of converted files would rise because all developers dealing with that subject could work together.
My largest hope, though, is that we will see someone developing a new, simple and fast GUI on top of this framework. Think of it as the Firefox of OOo.