How about a noob perspective.
This question has a related duplicate question
Implies a possible exact duplicate, does not have ambiguity associated with words like might and allows closely related questions to be consolidated via the links such that a new user like me could peruse and determine if any of them, especially questions with answers, actually work for my case. I can infer from related questions and answers, if any, if my initial question is related to something else I did not ask or if it is unrelated to my specific issue.
If the related question with an answer exists, helps me in some way I can't vote it up or comment on it because I'm a noob and only have 1<50 rep points which helps perpetuate this issue of creating duplicates since, less feedback was given or accepted. Reason; If I am unable to vote or comment and it is the answer for my issue I will likely never return once I applied the answer to my situation because it is fixed. e.g. I've been frequenting askunbuntu for a couple months now. The OP nor the Answerer ever know just how helpful the question and answer were to me because I'm not allowed to comment on a question or an answer that helped me. I also can't ask someone that has an answer if they can clarify something that may apply to my situation, which could help eliminate duplicates as well.
If the supposed duplicate question or answer that exists, is not specific to me I am left with no other means than to make a new possible duplicate seeking help on my specific case, which helps to perpetuate this issue, assuming I am so new that I have no clue if it IS related to some other question that is not marked This question has a related duplicate question
Usefulness: You could put multiple related questions together, each linked with This question has a related duplicate question, even if overlap happens thereby consolidating them quickly. Tags would consolidate as well providing a noob or an experienced user to find related issues and possibly determine if there is a bug related to the question faster.
Remember as a noob I might not even know the correct tag or category of systems related to my issue to even ask the right question. Therefore noob questions that are broad spectrum could be consolidated into a very helpful set of focused questions, for which some may have answers for noobs. And, experienced users could help focus the direction of these consolidated nodes of related helpful material simply by adding This question has a related duplicate question
This is an exact duplicate should bot be used because extremely qualified persons can have a tendency to place related questions together with a quick peruse of keywords and possibly not seeing some non-keywords that make it unique.