You're forgeting about damage.Dudu42: Have you considered that the Citadel gives a 100% defense bonus... and a Fort with a nearby Chinese Great General gives a 95% defense bonus? Plus the 45% attack bonus? Plus the GGs radius is 2 hexes in every direction and he can move if he has to run away, or after the position is no longer necessary?
A 100% defense bonus just doesn't seem worth it to me when a regular fort + great general is nearly as good, and is probably better when you're talking about a Chinese great general.
3 damage is pretty weak, but it damages EVERYTHING around it. Considering almost every tiles had a british troop, that was a lot. The Cho ko Nu in my city could kill the weakened musketeers (or rifleman, I dont remember, but Im almost sure they were musk). Usually, its better to weak 2 units than kill one and let the other full. The weakened units had no chance against the pike and were easy spot for Cho Ko Nu.
You should see 5+ units taking 3 damage per turn at the same time. Of course, if the AI knew to use the water (and Im talking about Elizabeth, who should use water a lot) they could avoid the fortress. So maybe fortress are useless against a human player...