Maybe this topic should become as "forum guide" with links to all topics, where this is suggested. So if u21 NT-s are suggested 10 times there are links to all those 10 topics about it. And then this topic should be sticky with heading "Suggestion forum guide: read this before you post new topic!"
If someone makes new topic about early discussed things, it can be moved easily to the end of earlier topic by mods.
And then all suggestions should also be rated/grouped how good they are. For example, some former Fluffybunny's suggestions can be classified "(Very) Bad idea", if most of forum community was strictly against it or it was clearly arguemented out. There can be also sections "Used suggestions" like some special attributes, "Suggestions in progress", "Suggestions in further future" etc.