Well how about comparing it to a French Keep? French Keep lowers cost of Arbalest and Knight by 25% With an upgrade, it lowers cost by 35%.
This by itself is already better than the Spirit Way Landmark. Ontop of this, you can build as many Keeps as you want, anywhere, which means you can apply this to all your production buildings.
Spirit Way has only a small radius and will not apply to production buildings build at the front line. Because of this, I suggested it should simply make all Dynasty units cheaper regardless where they are produced. See here:
Spirit Way is easily the worst Landmark in the entire game. The Great Wall Gate isn’t much better either. Its supposed to be an economy Landmark, yet it does nothing unless you invest into a 2nd Dynasty. And the cheapest unit unlocked for 600 ressources isn’t even a very good unit.
Zhuge Nu are outranged by Archers and Crosswbowmen and with Knights running rampant in Age 2 you can’t use them against 2 civs. They are also worthless against Man At arms. As soon as your opponent gets Age 3 you must stop producing them because they suck vs armored units.