resources becoming boring? bring in a bit of a twist: since we do not have any real source of unhealthyness and it's hard to have unhealthy large cities i suggest the following new resource modifiers - for example for alcohol or any other drugs:
Alcohol:
+34%

per city population size (with tavern)
+20%

per city population size (with tavern)
+1%

per city population size (with tavern)
means for a size 15 city with alcohol and a tavern building:
15 * 34% = +5

, 15*20% = +3

and 1% * 15 = +15%

. it's effectivly a trade of

for

and happyness.
aternativly:
+1

per resource (with tavern)
+1

per resource (with tavern)
+1%

per resource (with tavern) (this bonus could be applied to luxury resources like gold too)
so you need look out not to produce more alcohol than it's healthy for your population.
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and for fueling resource types:
+10%

with certain production building (factory?)
+2%

per
so a city with 100

production each round gets +2
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for fertilizer type resources:
+1

on every tile around the city with a farm (with a certain building). consumes one resource