There are config files all over the place!
I don't know if you've ever gotten stuck in the config file swamp, but I'm there now and it is stiiinnkkkeeee! Each Project in my VS2005 solution has a config file. There is one for the Unit Test case project, one for the web app (web.config), and now I've just added one for the Console App. Part of the reason for all of these config files is the fact that all the projects rely on the model library. You know, the library that does all the work.
Notice in the spiffy diagram, how the model library depends on each config file. This creates what I would call 'tight coupling' between layers of the application. The model layer loses resuability and independence. A sort of 'indirect cohesion' between the subsystems through the config file.
My first thought is to refactor the code to move the dependency on the config file up to the 'owners'. The configs are after all owned by these assemblies, so it makes sense for those assemblies to have exclusive interaction with the config files.
So, by the diagram, all interaction with the config file would be up to the config file owners. Settings would then have to be passed into the model as parameters. If this creates a long parameter list, I could group settings into structures.
As usual, foreseeing such problems is always beyond me and it will probably take me some time to work this out to my satisfaction. More postings on this to come :)