Earlier quoted context omitted.
Actually if you are changing a dependency right at the bottom of the chain, it makes things much faster as each compilation unit (assembly) is less likely to be coupled to the changed code. Large assemblies are the enemy of compilation time as you can't partially compile them (like you can with java individual classes).
Incremental compiler in C#: http://msdn.microsoft.com/en-us/library/aa691231(v=vs.71).as...
http://msdn.microsoft.com/en-us/library/ms379563%28v=vs.80%2...