Long time since I spent my words here (shame on me...), but I am in a middle of a great project that touches almost every MS technology: asp.net, WPF, WCF and even WWF. I want to talk here about known issue from Microsoft and not to innovate something but to share my frustrations in regadrs it.
Even WWF is a great technology, has very intuitive API and supplies fun of programming - which is very important these days (for me at least) it has a major disadvantage: VERY VERY VERY slow VS 2008 designer. I am talking here about very big WF that contains somthing like 15 state activities, which everyone of them holds very complex conditions, code activities, send & receive activities that exposed outside as a WCF service.
In the beginning (were I was young by 6 months) life were easy and the future sound even better, but this has been changed after more and more and more logic in the WF which turned it to be a WF monster that except of doing coffee it does almost everything...
My main insight in regards to it is to split every single state (also if it very small one) to a custom activities that each one of them (of course) will be placed in a seperate file and will hold all its logic. After it, in the main workflow file you could attach each one of them and combine the puzzle.
Click to read more: VS2008 Workflow Designer is Very Slow