That's a good point. It looks like currently we don't have that. It's just at the post level, which if enabled would allow them to delete any, including the topic.

I won't be able to get this into 7.3, but will make sure it's in for 7.3.1, which shouldn't be too long after 7.3 is out. It's pretty normal for the first dot release to come out pretty quick once everyone upgrades and finds a few things here and there.