I'm sorry you are having trouble converting. If you need help in specific areas, feel free to email us and we will be happy to give you assistance. We did these updates to help unify the look and feel across all our products. By consolidating all brushes into a single reusable repository, we're able to make sure everything renders consistently and looks great together. Our new native WPF control styles that ship with the themes updates also use the same brushes, allowing native controls and Actipro controls to intermix and render with the same appearance. I know it's a hassle with all the changes involved, but it's the only time we've ever updated themes like that and the benefits of this system outweigh the drawbacks of making such a drastic change. But also note that these changes were done in 2011.2, which was released 7 months ago.
The Navigation's "Converting to 2011.2" documenation topic talks about how its former expander styles were changed and their replacements. I believe we chose to discard the alternate style and combine it into a single ExpanderStyleKey for that case.
The general "Converting to 2011.2" documentation topic talks about how Office themes were split out into a separate assembly that you'd need to reference and execute a setup method on to activate. The steps to support Office themes are in that topic. It sounds like you didn't do one of them and are probably seeing the default fallback Aero theme, which is similar to Office Blue.
Remember, the documentation topics on conversion are your friend. Both the general and product-specific ones. They often can lead you in the right direction on things. Or if you get stuck, please don't hesitate to email us.