@Thalassicus: Thanks for your thoughts.

I understand completely where you’re coming from re: the fish. Re: the watermill, the ability to apply multipliers to base city production is another reason why I was thinking of adding 2 hammers to them (the second at machinery); when combined with the 2 hammers you get from the city’s central hex, a watermill would then give you 4 hammers in the city, already enough for a 25% bonus to give you a free hammer. That said of course, the advantage that adding a third hammer to an engineer specialist will give you is that the buildings that provide the engineer slots aren’t all confined to riverside cities in the way that the watermill is. You’ll still of course need the food to feed the engineer though - which has now been made slightly harder to get by your (wise IMHO) changes to maritime city states. Assuming the food can be found though, I just wonder if buffing engineer specialists even further is indirectly (albeit subtly) promoting the pursuit of some kind of specialist economy to obtain hammers. Don’t forget too BTW that engineer specialists see their value rocket (relative to a mine) if they can generate a GE.
As an aside, I’ve been having a further think about the watermill and I’m becoming more convinced by the minute that this building should boost hammers, not food. Giving it three hammers for instance (of which maybe one or two come at machinery) would make it pay back in 40 turns, identical to what you’ve amended the windmill to. In exchange, it could lose the food advantage that it gets.
FWIW, I’d then be tempted to go even further and remove the improvements you’ve made certain hexes receive from the smokehouse, and add them back to the hexes themselves. You could then return the granary to its traditional role as a storer of food, even if at just 5% or 10% - and remove its ability to provide 2 extra food to compensate. As Krikkitone’s post in the attached thread shows, a 5% storage rate would mean, for example, that 2 food (identical to vanilla’s granary boost) gets stored at 4 pop, 6 food at 10 pop, and so on:
http://forums.civfanatics.com/showthread.php?t=388877
The ability of the granary to store food could even be made to rise to 10% or as much as 20% upon the discovery of some other tech; calendar would’ve been ideal IMHO had it sat somewhere similar to where it was in the Civ4 tech tree. Of course, any changes here BTW would obviously result in downward changes to the food stored by the hospital at biology.
In all, these changes would (i) give riverside cities precious early hammers (ii) keep the granary in its traditional role as a food storer (and make it better able to support city growth, since the amount of food required to grow to the next pop rises exponentially in Civ 5, as the previously mentioned thread shows) and (iii) reward players for improving their hexes. Of course, this makes non-trivial changes to the mechanics used in Civ 5 - in particular, it would make starts a little less even. These changes would also sadly undo your good work with the smokehouse (unless you retained it as another building (EDIT: eg. available at construction) to avoid increasing tile yiellds on cattle etc. and keep starts even). As a result, I can understand completely why making these changes wouldn’t necessarily appeal to you.

But I’ll throw the ideas out there and see if anyone wants to look at using them.
Moving on from the granary, does the modding community have access to the code that governs how the AI chooses where to expand borders in a city? I ask BTW because at the mo’ I currently have the AI ready to add a plains hex to New York when it next pops its borders – even though it has a perfectly good cattle hex within reach!

I’m just wondering if there’s some way of allowing the human to over-ride the AI choice of hex that the city gets at the next border pop.
One last thing Thalassicus; as my game progresses, I may well come up with other ideas, some good, some bad, some ugly - I’m sure.

Where would you like me to post any thoughts; in this thread, your separate mod threads, or elsewhere?