In short I'd like to have remove "username" as a trigger for the "Moderate registrations when this many warning flags are detected:" option. With some user names being pretty common (eg: "Genesis" was the last one that got caught) I'd prefer to only check the IP & email values.
Yeah the default setting of 1 will block common names all day long. You have to turn it to 2 for it to not falsely ban people. But I would rather be able to configure it like you suggest. Always prevent registration on a known email or ip without requiring it to have another factor and then at the same time not ban on names.