Word for devastativeness?

Destructiveness is an actual word and it seems to match your criteria.

I agree with @Abody97 that destructiveness is your best bet considering the provided criteria. A less attractive option would be vehemence, which is sometimes used to describe storms.

If the criteria are flexible, you could consider something along the lines of:

• Scale of devastation
• Magnitude of impact
• Intensity of impact
• Severity

Magnitude and intensity are often used to represent the effects of events such as earthquakes, tornadoes, and cyclones.

Perhaps ironically, I think the best word here may be impact, specifically in the third sense identified in the link.

"Scope of impact damage" seems to cover your need for that category. You're addressing the condition that the object does achieve impact and then you're specifying the need to provide a scope of the damage.

If "destructiveness" feels too clumsy for whatever reason you could opt for "destructive capacity" or "devastative capacity." Seems pretty clearly to me to refer to how capable an object is of causing destruction.