I was looking at the A_New_Dawn_GlobalDefines.xml and noticed
<!--The Time and Gold to Build a Route over an existing route is reduced by the time and Gold already invested in the previous Route-->
<DefineName>ROUTES_UPGRADE</DefineName>
<iDefineIntVal>0</iDefineIntVal>
How come you don't use this currently? Also maybe something like this could help with the current problem where people prefer to pillage there old improvements rather than wait for them to upgrade. Part of the problem obviously is that the new improvements can't be built over the corresponding old ones. Unless you change a mine into a windmill and then into the new mine version.
<!--The Time and Gold to Build a Route over an existing route is reduced by the time and Gold already invested in the previous Route-->
<DefineName>ROUTES_UPGRADE</DefineName>
<iDefineIntVal>0</iDefineIntVal>
How come you don't use this currently? Also maybe something like this could help with the current problem where people prefer to pillage there old improvements rather than wait for them to upgrade. Part of the problem obviously is that the new improvements can't be built over the corresponding old ones. Unless you change a mine into a windmill and then into the new mine version.