Helping the moderators and contributors of the courses.
Hi, everyone ! I have an idea. How about to ask duolingo learners for the better translation of sentences? Because sometimes (many people agree, I suppose) there appears a translation which will never be used by native speakers to express their thought. In order to improve Duolingo and help its learners to speak properly in the language they are learning, I suggest contributors to ask us about more suitable translations. Otherwise, seems like you are a robot using these expressions given as "the right answer". Hope, this post will be noticed.
if there is a translation that you think is incorrect you can always report it (or if a better translation is not accepted, equally report that it should be accepted).
I am pretty sure that the translation that is displayed by the program once you have submitted your answer is considered to be (on of the) most idiomatic translations. The course contributors already mark translations as 'the best ones' when they create the courses (and they are native/ bilingual speakers, so they ought to know!).
Other translations are often accepted because a literal translation is not necessarily wrong, and a lot of users give it to be on the safe side. So I think your suggestion is good, but already kind of implemented in the system. :)
Perhaps it has gone un-noticed but when a question is answered Duolingo invites you to a discussion about the answer. It is an excellent way to learn as many experts and a few of us dubs frequent those areas.
If the question or answer is still unsatisfactory there is a button for that. Duolingo will even give thanks for the input.