I actually really like Money Walls however i think that it wouldn't benefit the server right now due to the lack of players. But it is a really good concept so they could consider spending time on the game soon when Cubecraft hits 7k-8k players at once.
A lot of YouTubers used to make video's in this game aswell so it could be a way to bring a big part of them back to the server.
Maybe they could bring Money Walls back but completely different & more modern and updates as in bug fixing, this will most likely not be right now i think since the team is probably focussing on more important things.