Great Buildings
A few comments on two of the great building options activated after building multiple government palaces.
The Great Tool Factory: Currently reduces food by 2 if there is a river. Introducing a penalty in reduced food for further progress in metal industialisation is an interesting idea, and probably realistic. However, this can be avoided by not building the Great Tool Factory in a colony with a river - and usually you have a few options of where to build the great factory. Perhaps it might be possible in future releases to have the reduction in food applied at a settlement level, via a negative building bonus addition/subtraction for total food, instead of at the square level impacting only 1 river food square. Then a player would not be able to avoid the food cost for mega industrialisation - all settlements would incur it irrespective of their food or water source.
Great Arsenal: From memory this currently requires 900 hammers, 200 ore and 200 tools for the benefit of +1 gun per gunmaker and 10% increase in production. While eventually your gun numbers will increase it seems to me that the requirements for this building are a bit too high and the payoff time is too long. If I think this, and I probably play bigger and longer games than most other players, then it is moreso for other players.
It seems to me that because in this mod you need a magazine to build the attacking cannon, most of your settlements will be developed to magazine level in order to maximise cannon production for the final battles. So I think that most players would be better off using excess ore and tools to take 4 of these magazines to arsenal level, increasing local gun production by 40% at each location, at the same time as building the cannons, instead of building a Great Arsenal at just one city (and then having to wait for an eventual buildup and distribution of guns).
Plus with learning by doing in place in this mod there is some benefit in starting to produce guns in many locations using colonists, as most of these will convert to experts automatically before the final WOI (doubling the output per person at each location, and increasing your total number of expert gunsmiths and guns). Whereas I expect a great arsenal would only ever be operated by existing expert gunsmiths.
I haven't done any detailed calculations, but it just seems to me that the balance for this one is a bit off and the requirements for the Great Arsenal could be reduced a bit, otherwise not many players would build them.