fun until it's really frustrating
The biggest problem is that when you send a soldier to a location, it frequently gives up midway because its path was temporarily blocked. It's really frustrating when your basic game controls only sometimes work.
They also constantly shuffle around the rally point for no reason while blue stands in the way doing absolutely nothing. Other than being distracting, it traps soldiers in the middle. To use your own troops it's like untangling necklaces quickly while they're spinning. It's not fun, mostly anger inducing because you're usually in a hurry.
Simple fix: Let them walk past each other and don't allow them to give up when you send them to a location.
Smaller problems with movement: New spawns take a really long time to start heading towards the rally point. I don't see why it's not immediate. Sometimes soldiers go to an old rally point and stay there for a while. They also take very meandering routes and you can't help them by placing grass blocks. I think this can be fixed by running the path finding algorithm at each step or every other step.