You were right, this thread IS awful (except for page 4).
The question arising in my head is: Why? Why even start such an argument? What are you trying to achieve here? People have different opinions on what synergy is but so far they've been coming to terms on which cards synergize with each other just fine. Individual notions of "synergy" in general discussions on strategy have been completely sufficient for years. Why is it so important to you that people now assume yours?
What's the point in trying to define what Village and Smithy have going with each other, when all there is to know is that in an engine you want splitters and draw (which are provided by Village and Smithy) and the more copies you have of both, the more card you draw total? You can say, they have synergy, or they work well together in an engine, or you need both (or similar cards) to draw your deck.
The conclusion is always the same; they are both engine components, or, in broader terms, parts of a specific deck you need to build to pursue a specific strategy. If your strategy requires Apothecaries and Coppersmith, or alt-VP and Hoard, it doesn't matter whether they have synergy or just add their values, as long as you have a reason to include those cards in your strategy.
This is what this forum is about. It says it in its name: Dominionstrategy; not Dominionterminology!