Imagine you've created a trade with country A and the trade route is through country B. Now country B goes idle, and the AI cancels the trade route.
I think the idea is interesting, but fails in this environment given the frequency with which active players become inactive, unless you made trade routes through AI countries automatic, which would defeat the purpose.
I think that we could consider the AI nations as a weak nations that very often in the real world just surrender to the will of theirs bigger neighbors. Maybe a mechanic could be added that for every country that has at least twice as many provinces as the AI country, the trade agreement would be automatic. I think there are easy ways to solve that. The exciting thing would be the diplomatic task of creating a trade route and access to the sea by the landlocked countries. I think that this would give a huge reason to use diplomacy and be engaged.
Even our current trading system is making the trade very boring, because we don't know with which countries are we trading. It seems like everything there is anonymous, which could also add a nice twist to the game if for example we knew that we always buy a resource A from a country X and now we see that a country Y is attacking country X. Well to protect our supplier and cheap source of the resource A we could join the war and protect him, etc. The current system is just very arcade'y and in a game like this it doesn't make sense unless (and this is something I fear the most) the game is dumbed down on purpose just to attract more people to click around mindlessly and spend more money.