I'd like to request a feature to be able to search task comments only. Also if the search can be restricted by the normal filter options (clients/projects/milestones/modules/status/priorities etc) that would be good.
Regarding the second part of the request the advanced search can be used to perform a more granular search. For example you can search for all tasks assigned to a certain person, that are of a certain status for a particular client/project/module/milestone, etc. It sounds like it might do the trick. If you click on the advanced search option in the footer here are the advanced search options for tasks: