The plan for OpenOffice 2.0 is laid out in a document called the Q Concept. It's a comprehensive roadmap to making sure OpenOffice 2.0 is a truly world-class office suite capable of capturing a large share of the market.
The main thrust is that OpenOffice 2.0 will be much more compatible with Microsoft Office, and users of Microsoft Office will feel more at home with OpenOffice 2.0 than they did with previous versions.
For instance, OpenOffice 1.1 has a pretty good database frontend, but it's a bit hidden and hard to get used to; OpenOffice 2.0's database frontend will be much more intuitive.
(Note: these are the outstanding issues in the real OpenOffice.org bug tracking system; the data is a bit untidy, so you might have to play with it for a while before you get a feel for what it means.)