Replacing translation ratings with something potentially better.
Instead of asking learners to rate the translations of others, the following could be done instead:
show them a few translations from other people and ask them to examine these for ideas on how they could improve their own translation and/or suggest edits to others
the score for your translation shows how closely it resembles popular translations/translation fragments
the scores for your translations change over time as Duolingo accumulates more data about them
you can rank your translations by current score to allow you to see where you have scored well and where you could try to increase your scores by modifying your translations to something better and/or suggesting edits to others
What do you think?