I don't really agree with this idea; it's essentially making promises to our community that we sometimes can't keep. I recall Mac promising Skyblock by the end of 2016. It is now 2018. Simply put, we don't tell the community when things are planned for release because things go awry and we end up disappointing everyone. Adding this accepted suggestion sub-forum would just increase the number of potential promises to the community that we can't keep.
Developing for a server this size is pretty tough, and a lot of times, things have to be scrapped, altered, or left out until a later release. We don't want someone to suggest a skywars gamemode, have Cam or Hubert approve it, then 2 months later when we have a skywars update, discover that this gamemode is impossible to implement. We learned our lesson from promising things to the community; we don't write checks we can't cash anymore.
For a small bit of insight, the two mystery armor stands in the lobby were my ideas. They were meant to be released alongside the new lobby, but due to some very minor issues, typos, and managerial stuff, we pushed the release back to the 18th. I'm an adult (shocking, I know) so I can understand when things don't work exactly as planned; the world isn't perfect and neither are we. I'm not too bothered that the release was pushed back a week. If we promised players something on a specific day and didn't give it to them on that exact day though, that makes us look bad. We don't want to look bad. We want to give our players things that they want, but we don't want to tie ourselves down to a promise that we can't with 100% certainty keep.
Now, I wouldn't be against having this sub-forum if we moved the threads there AFTER the suggestion was implemented. We do take suggestions from the community with every update; we just don't normally publicize it. I have no problem with giving credit where it's due, and as someone who's made multiple suggestions that have been implemented (cubelets, leveling system, like an entire page of hats, several duels kits, hourglass, snowman survival, next week's release, and more!) I would absolutely love for people to get recognized for their contributions to the server. Again, AFTER we know our devs can do it and AFTER the idea is implemented.