Research-
Caravan Reinforced: Now when caravans are attacked it will take 3 seasons for them to engage battle. You have the option to save the caravan,
Caravans should also increase there usefulness if they maintain the same route or if they are veterans of trade. This will make you want to save a caravan all that much more.
Other.
Caravan Stallions:Increased
Caravan Increased Cargo: Increase money
Caravan Market: Now offers +1 to all your existing resources.
I'm not a huge fan of trade but when I keep getting messages of my caravan being destroyed well.. its annouying =P
Another option would be instead of Outlaws or Bandits type units destroying the caravan it robs them, which will resort in you losing money. Destroyed Caravans should leave a broken caravan marker there for champions/sov to pick up.
(I have more ideas on this)