There seems to be a built in barrier for entry on A51, where if there isn't enough vocal demand (ie, the number of participants doesn't significantly outweigh the number of lurkers) then the proposal fails? That's likely "working as intended" for the site which only wants to host and commit bandwidth and server space to things that have long term sustainability.
If you want people to become engaged, you have to make them choose to engage, and keep them coming back.
Some suggestions? Google Hangouts for discussion of gamification topics? Actively place everywhere possible "Vote" and "Comment" and reassure people they won't get laughed out of the room
I have a problem with the term "gamification" because it sounds like trendy buzz words for some sales and marketing ideas. Even though I know better now, it's unlikely the masses do. Maybe make it - "Gamification: Beyond Badges" or something to that effect.