Mmmh... "impact" has the underlying meaning that it will have some negative effects on some existing applications, which is not the case for 99% of changes (we are careful about back compatibility).I was looking for a name, and I found weight as well as a good choice.
I have check the weight definition, and I found "Gravity" as another choice.
Please not more abstract than necessary :)
@importance or @impact is a better choice IMO.
Joerg
