Auto-renewing would not be a good idea, as often the trade value for external trade routes fluctuates and there are often better deals you can get, even when trading within the same faction. Auto renewal may alleviate the micromanagement, but you'd lose out on better deals in the long run. I'd much prefer a better way to sort through trade routes and assign them from the trade overview screen. Curently the yields are all lumped into one column. Moving them to seperate columns and making them sortable by highest would be most helpful. Being able to assign any trade unit waiting for orders would be the cherry on the top.