For some skill passives , they will not be able to be allocated if the tree has a "blocking" passive on it.
Take nova for example, you can branch into the Lightning, Ice, and Fire variants. You cannot have your nova be all of the elements.
So when someone takes the Lightning Nova skill, the Ice and Fire Nova passives cannot be allocated.
Not all skill passives restrictions will happen at the start of the tree like it does with Nova.
Create a system that allows to set "BlockingPassives" or something that prevents someone from speccing into a skill passive if a blocker is allocated on the tree.
Summary
For some skill passives , they will not be able to be allocated if the tree has a "blocking" passive on it. Take nova for example, you can branch into the Lightning, Ice, and Fire variants. You cannot have your nova be all of the elements.
So when someone takes the Lightning Nova skill, the Ice and Fire Nova passives cannot be allocated.
Not all skill passives restrictions will happen at the start of the tree like it does with Nova.
Create a system that allows to set "BlockingPassives" or something that prevents someone from speccing into a skill passive if a blocker is allocated on the tree.
Reasonings
Prevention of some abusive strategies