Duplication = more than one entry for the same person, right? Person appears twice on the family tree.
Are you aware that you can get rid of duplicates? Let's say a parent of Person A and Person B are the same person, and that person now appears twice in your tree. SO....delete the parent of Person A, then for Person A's parent, select the parent of Person B.
That's more or less a merge option, available already, leaving the control with you to make a decision on a case-by-case basis, whether the person is truly a duplicate or merely similar.
If the merge option you want is global, that wouldn't work, as so many similar people lived. The software can't spot the duplication and make a decision for you. (I'm flashing on auto-correct with text entry - yikes, what a hell that would be in genealogy).
If the merge option you want offers you a choice on a case-by-case basis, and I think that's what you're saying, it would save you some time but nonetheless you can now achieve the same effect.
Yes, I can see how being frustrated about that one difficult line in your family tree could lead to your post. If you get rid of your duplications -- spend a Saturday doing that -- you'll probably help the software generate better hints and possibilities for furthering your family line.