Now that skill trees are a thing, having the ability to swap/migrate points from one node to another without having to deactivate all the children nodes would be nice.
Take the following Psyker talent path for example:
Wrap Expenditure → Battle Meditation → Toughness Boost → Assail → Toughness Damage Reduction → (whatever else going down).
If I want to swap out Assail for Smite, I need to deactivate the Toughness Damage Reduction node and all of it’s children, even though they would all still be accessible with Smite in place of Assail. Maybe the interaction with talent point allocation could be a “allocate then validate” process. Players allocate their points freely (no locking of nodes), and just have the UI/X indicate invalid allocations the player needs to fix before the talent tree gets saved. However, I wager the majority of players won’t do enough talent swapping to warrant the resources of implementing anything like this.