Defensive "Catch"?
 

Maybe I'm crazy, but I had an idea. What if any unit with an overland movement greater than 1(the whole unit, not just the comm) could have up to 3 "Catches." Ok, here is how it would work. On a turn, you can choose a new order called "Catch", and you get up to three catches, set in priority 1 to 3. What it does is, the unit does NOT move, and cannot move in this turn, unless it does a "catch." The way it would work is during the host phase the unit Queries all the catches in order, if a hostile unit moves into a catch it moves, and lower priority catches would be then ignored. Regardless of movement speed, the catching could only be done one province away. I personally think that this would make defending an empire's border 1000 times easier, and would be a good addition to the game. Visually, the catches could be green (instead of blue) arrows.

Re: Defensive "Catch"?
 

Great idea!!

I would rename it to "Strategic Interception", though - took me a while to figure out what you were saying... at first I thought it was weapons being used defensively.

Another approach would be (similar to Stars!) an "Intercept" order. And army with "Intercept" commands would act just like an army on "Defend", but would automatically move to defend any adjacent province. You would not be able to set a priority, so by default, it should intercept the most lethal threat.

Re: Defensive "Catch"?
 

I fear it might be too powerful.

Something I would like, however, is that the armies do not move at once. For example, if I attack a province with an army with a minimum speed of 2, I would attack before an army with a speed of 1 has the time to move out. This would make armies consisting of cavalry/flyer great raiders and make the light/medium infantry more useful and powerful, and give huge fat armies a harder time behind the enemy lines.