There are quite a few ways to improve on Scythe's poor interaction. Another way would be to make encounter cards affect the neighbors of the active player. For example, Pay 2 pop and steal a mech. Instead of just loosing the 2 Pop you have to give 1 to each neighbor. Which not only increases interaction but fits in with the story of your faction being mean and the civilians hear about it and show more favor to your neighbors
You should playtest and post your variant. Let us know, I'm always up for trying more game modifications. The variant I've posted has been play tested a number of times with the base rules and works well for my game group.