The npc question reporting system only works if and when devs have time to get ingame and check, the system does not tell them if the question was in a quest or a general question, with so many npcs ingame in quests and not, it is hard for them to figure this out.
So a dev has to go in game to see the log? If so, thats madness. They should have an option to browse them in notepad, filtered so that it is readable. A table where they can see what was the last informative NPC response the player is most likely asking about and where the dev can read all answers of the NPC, quest responses, so they can know why players asked these questions and by this add proper triggers.
If there is only a list of sentences the npcs didn't understand without even the npc name they was asked to and it is available only after logging in game, it is connecting to our so unstable server... This feature is near
useless 
This pretty much explains why you and others insist people make bugreports and use other methods.
But here is a fact, if the logging system wont start to have a use, there won't be any progress. People will continue to behave as they are and you will receive the same amount of reports. This is how it works. This thread will maybe motivate a few people to make some reports, but there wont be any breakthrough, which will allow the devs to fill the NPCs dialog holes on much greater scale.
If a setting dev can't even look though the npc dialogs to see what things from it lack an explanation, without logging into the game... this is efficiency tragedy, seriously, it must be terrible.
It is the devs who should have easy access for these, because it is they who can viev and edit them in an efficiet way. It is not a player with a tiny chatwindow and 10 fps and who can't focus purely on the problems, because they have to play a mind game first of guessing if the NPC really doesnt know what is asked about and alike.