It would be nice if there was some small icon/badge attached to each power icon in the diplomacy box (top left of the main window) which would indicate that a power has strategic (one icon) or luxury) another icon) resource that you don't currently have access to.  

As a merchant power I am finding myself constantly checking every diplomatic partner every 4-5 turns to see if they have something new for me to buy.  This is a lot of work for something which should be simple and it's important for the merchant cultures to really take advantage of their power.

Good suggestion.

It would be nice if eventually we got a trade screen in which you could see all trade routes, and buy things directly from there.