Almost all improvements improve with higher tech and/or civics besides pastures, plantations, and camps(the 3 that jump out at me, I might be missing a few). While the resource is a great bonus, when I have for example 4 silks in an area, I find that I build plantations over 2 of them at max(unless I really need to trade them), and put farms, watermills or towns over the others.
An idea is to have these improvements scale up through the game like other improvements. An easy fit would be to have the recon line give a bonus or two to camps and perhaps pastures (say a commerce boost at animal handling and an extra point of food at animal mastery?), and to have perhaps mercantilism and/or slavery give boost to plantations?
The other route would be to give increased benefit for having more than one of a resource(guilds).
An idea is to have these improvements scale up through the game like other improvements. An easy fit would be to have the recon line give a bonus or two to camps and perhaps pastures (say a commerce boost at animal handling and an extra point of food at animal mastery?), and to have perhaps mercantilism and/or slavery give boost to plantations?
The other route would be to give increased benefit for having more than one of a resource(guilds).