One of the ideas just being discussed at work is around having a lightweight way of creating tasks related to a diff. For example, if there's a side issue on an open diff that deserves a separate discussion off of the diff, or if there's a diff that's already closed but you want to do some follow-up that doesn't call for a "Raise Concern".
One design would be if you left a comment or inline comment with some special new markup like 'Filing {TNEW: Fix this ugly hack} for this'. Then Phabricator could process this by filing a task like "T-3000: Fix this ugly hack in D123435" and the original comment would end up reading as "Filing {T-3000} for this.
@epriestley, what do you think?