I wouldn't mind that, that you'd control the notification both for your journal and your comments elsewhere.

Though I think the option discussed above with a flag to trigger notifications would probably easier to get used to, and avoid having yet more settings about privacy and exposure that you have to keep in mind. Instead you'd get an easy way to ping someone for a discussion only if you want to, instead of it being like a Voldemort invocation, where you'd either need to take protective measures via various opt-outs or resort to "he who must not be named" monikers to avoid triggering this stuff.