There is already something similar to this gamemode known as "cakewards." I think it would be a bit redundant to add bedwards; however, I like that you were thinking! :)
Heya! This has been brought up in the past and always been denied. Like @Austinly said, we have a very similar game called Cake Wars which is the same concept as bedwars. You eat other teams cakes and then eliminate them to win. The reason we don't have bedwars is because Mineplex doesn't like to blatantly rip off other servers. The main thing that made Mineplex so popular back in the day was that it had its own and unique games. If you want bedwars you have a bajillion other servers to choose from, but we're the only server (that I know of at least) with cake wars. While I love that you're coming up with idea to help the server, why don't we think of ideas to improve the games that we already have, or bugs we can fix instead of adding whole new games!