this has been suggested a million times at this point and i will keep saying the same thing; i disagree.
the server removed it with a reason, probably because it wasnt too popular at all. and especially now the playerbase of the (java) server went down a lot compared to the old days, i think adding it back wouldnt make much of a difference.
its also a quite long gamemode, which makes a lot of people leave halfway and by that, ruin the endgame.
i think if they want to improve the server, they have to focus on what they have right now and add smaller/more original gamemodes.