There's a certain site that I visit, that allows people to post their ideas, and then allows other to vote up on them, increasing the ideas rank. The key to this system, in my opinion, is that each user gets only 3 votes at a time. You get a vote back if an idea is slotted to be worked on for implementation, or if you manually take it back, but either way, I rather like the feature. It gives space for players to very articulately describe what they'd like to see changed, and to allow others to vote upon how much they want to see this. Another great thing? It doesn't force staff to wade through layers of idea suggestions, nor does it force them to implement a suggestion. It just gives an easy sense of what would be most popular for them to implement, if it's feasible/the right time for such an idea to happen.