Just a short post on how to approach designing and implementing large or complex workflows using the SharePoint 2010 workflow template in Visio 2010 Premium.
As you probably have heard Visio allows us to use this template to model our SharePoint workflows in Visio with a new shape set and then export it directly(as a zipped XML, *.vwi file) into SP Designer for the developers to 'hook up'.
I am currently modelling quite a complex / large workflow and I can see its going to be an absolute beast to contain within a single, sprawling Visio workspace. After talking with the development team it was decided that breaking out into 'tabs', although not as powerful as the linked sub-process of standard models, would be sufficient for development.
Rather than exporting and maintaining as a single .vwi file, the 'export' option of the process tab only exports the contents of the current tab - so it is possible to break detail out into 'tabs' and export as separate .vwi files, which in turn are imported and implemented into SPD.
You wont get as much detail in your workflow visualisation if you implement in this manner, but you could always link the tabs or .xml in the .vwi's together at the end to get a single (if not complex) workflow visualisation.
Will post more on SP2010 workflow design in Visio as I come across - which be the looks of things, will be a lot!