Custom "currents" per community
Short, concise description of the idea
Instead of simply "music" and "mood", replace it in the client with a variable that the community's moderator feels is relevant to their targeted group. For example, "Calories" for a weight-loss group or "Movie" for film discussion communities.
Full description of the idea
My idea would be that when you specify in your LJ client which journal you wish to post in, its "Currents" (Music, Mood, etc.) would change with it to something specific to that community. This wouldn't prove to be extremely useful, but I feel it would give it a more custom feel when creating a community. Say, for example, in my community the poster could have the option to post their computer specifications or their case model. This would save a lot of needless space in the post where they would have to explain all of this information, so they could just get to the point with what they're telling.
An ordered list of benefits
An ordered list of problems/issues involved
An organized list, or a few short paragraphs detailing suggestions for implementation