1st of all: Subjects are allowed to take sides. Why? Why my vassal is fighting a league war, when I'm neutral? It doesn't make any sense.
2nd: why would a country call whole league when attacked by a third country? The religious league war is already on, I want to DoW protestant league leader. But no, it would call all their league, includind (from 1st) my vassal. How is DoWing a league leader (fortunately- only him) different from DoWing a country fighting in coalition war? Call You regular allies, not the whole damn league.
3rd: The whole thing with truces. You can't join a side if having truce with the emperor, the leagues aren't dismantled if the emperor has truce with at least one heretic elector. It makes sense at first glance, but it's not practical. There are ussually so many wars in HRE, that the leagues are not dismantling for centuries. There should be another, hard, cap. After, say, 100 years after the leagues are formed and no RL war was declared the leagues dismantle regardless of anything.
2nd: why would a country call whole league when attacked by a third country? The religious league war is already on, I want to DoW protestant league leader. But no, it would call all their league, includind (from 1st) my vassal. How is DoWing a league leader (fortunately- only him) different from DoWing a country fighting in coalition war? Call You regular allies, not the whole damn league.
3rd: The whole thing with truces. You can't join a side if having truce with the emperor, the leagues aren't dismantled if the emperor has truce with at least one heretic elector. It makes sense at first glance, but it's not practical. There are ussually so many wars in HRE, that the leagues are not dismantling for centuries. There should be another, hard, cap. After, say, 100 years after the leagues are formed and no RL war was declared the leagues dismantle regardless of anything.