One time i was playing mc and i was on the edge of a ravine - seeing if i should go down into it, i had all my super good items, and a zombie hit me off the edge and when i hit the ground i had 1/2 a heart left! it was more scary than finding Chica V01 on FNAF2!
Ok so maybe do control points, or a payload mode (where one team tries to roll a mine cart with tnt to the other teams base before the time expires)
Those are some gamemodes ive been waitng to see in minecraft, although Mineplex has controls points, I'd like to see another server with it. Those are my ideas, tell me if it helped