When the Ice Nova Passive is allocated on the Nova Tree the Nova Skill should be turned into Ice Nova Skill
The ice nova skill will have slightly less damage, 10% less damage.
So if the damage roll range was 10-20 it should become 9-18
It should also apply a "Chilled" Debuff for 5 Seconds
The ice nova should also visually change both the icon in the Hotbar and the visual effect when using the skill itself to signify the skill has been modified.
Reasonings
To add in variety and more depth to the skill system
Summary
When the Ice Nova Passive is allocated on the Nova Tree the Nova Skill should be turned into Ice Nova Skill
The ice nova skill will have slightly less damage, 10% less damage. So if the damage roll range was 10-20 it should become 9-18
It should also apply a "Chilled" Debuff for 5 Seconds
The ice nova should also visually change both the icon in the Hotbar and the visual effect when using the skill itself to signify the skill has been modified.
Reasonings
To add in variety and more depth to the skill system