I'm sorry to criticize this feature, because I know that someone took the time and effort to implement it with the intention of building something useful, however, as it stands, I don't like it one bit.
Here are my considerations.
I think that seeing the solutions can be helpful to learn a new language only after attempting to solve the problems in that specific language. You can't assume that if someone solved a puzzle in C, its solution can be easily translated in Bash or Clojure. Fighting with different paradigms and language idiosyncrasies is an important learning step.
Moreover it can be discouraging for honest users having to fight more to reach the same rank as copy-pasters, unless they become copy-pasters themselves. We don't want to teach that looking at someone else's code and saying "I would have done the same" it's equal to actually doing it, do we? Somehow I think that it becomes harder to achieve higher position just by copy-pasting, so it's more a new user problem.
As stated by others, the language specific achievements incourage people to learn new things. They got me and other players, like @player_one, to learn Clojure and new Bash magic.
For these reasons my suggestions are:
- show the solutions only to people who achieved 100% with that language;
/* I don't know how it currently works with extra achievements, I guess they should be taken into account too */
- keep the achievements as they are (and maybe add some for the highest voted solutions?);
- give me 1 million dollars in small bills and an helicopter with enough fuel to reach Mexico;
- allow people to choose for which puzzles share their code (to avoid leaking optimization solutions).
As a further cosideration, I think that the issue originates from the will to offer a challenging place to prove one's skill and to teach coding. Nothing wrong with it, I like the idea, as long as one purpose doesn't impede the other. Trying to add a didactic factor to the puzzles is taking away some of the challenging one and this is why people don't like the change. I think you can find a balance this time, but maybe it would be better for the future to keep different purpose stuff in different sections (I saw a couple of "teaching puzzles" on the forum and I think they deserve a section on their own).