The full list of changes is in the KB release notes here. I see just a few change notes there related to Workflow:
- XAML support: Workflow files that are XAML based pick up refactoring events from their code behind files.
- XAML support: Refactoring and “Go to Definition” without having opened a XAML file works unexpected when you interact with XAML files. [Hopefully applies to WF]
- VB Compiler Fix: Delays in large Workflow Foundation projects may be experienced when you switch focus between expression fields.
Aside from this I don’t see much WF-wise in the patch notes – still I am pretty sure there will be minor fixes which aren’t listed, and also some of the WPF framework bug fixes might help with designer stability or performance. I hope you can notice some improvements.