It would be great to have the option to cancel builds when the orphaning is calculated. That is in DefaultOrphanedItemStrategy.java -> orphanedItems it checks whether it is currently building and skips the item (I would like to see that the build can be canceled).
We are using the gerrit-code-review-plugin and having such an option would save us CPU resources when a new patch set is uploaded as the build result of the old patch set becomes obsolete once the new one is uploaded.