I think a lot of this could be covered by two principles that are often quoted but over looked. The first is, KISS, keep it simple stupid. The second is single responsibility.

When I design software, I apply both of these to every facet of the system (though I admit sometimes not as well as I should). The end result is I might not have a ton of interfaces and hierarchies. It might not handle curve balls as well as an abstract MachineFactoryFactory could. It does handle everything that we've thrown at it however.