Seriously…the rewards aren’t good enough for the effort to find 3 players to help you open it.
Maybe make it give 1 guaranteed set item or wisp for the 1st time opening the chest every day or something like Bestiary did…or just triple the loots for the heavy chest ornate. 
There’s still ornate chests in OW? Lol, i havent opened one of those since first month, useless chest really
Players experimented with these chests in the first one or two weeks after the game’s release, realised that the contents were usually not worth the time / effort it took to get four people to click on them, and pretty much ignored them from then on. That’s because the contents were usually 1-3 yellows and blues and a small amount of gold, i.e. in the time it took you to get 4 people to the chest, if you’d just spent the time farming mobs, you probably would have earned more materials / gold than the chest would give you. A couple of months back, when they added a single Monstrous Essence into the chests, doesn’t alter player behaviour which has learned that these chests are effectively worthless.
They need to have a something worth the time it takes to get 4 players to them, i.e. a guaranteed legendary or set item in them otherwise players will continue to ignore them.