Ways to improve diplomatic friendship

[HerrDoktor]

People are complaining in other posts about how the current version of the game undermines good diplomacy and favors too much warring. Now, how about we discuss some ways in which having friends could be more interesting to the human player?

I come up with a single idea for now. What if we make trade routes not to depend exclusively on improvements and civics, but you also can gain as many trade routes as good trading partners you have? Also, your relationships with such AIs could improve the quality of such routes. In other words:

*You will have an extra trade route in every city for and with each pleased trading partner you have;
*You will have two extra trade routes in every city for and with each friendly trading partner you have;