Generally skyblock is a fairly mundane play-through. Because of this and because of the self-sufficiency of everyone's island there is no reason to collaborate, trade, or engage in player to player commerce. My suggestion is the introduction of pve missions, dungeons, arena waves etc. These would be replayable with a loot system that resembles crates. However, my intention would be to take advantage of and give value to the custom enchant system that is already in place. The loot from these missions could be custom enchanted gear, isobux, xp, and others. The loot would help players to take on more dangerous levels (hopefully together).

The whole point of this addition is to give skyblock gameplay something to revolve around. Players improve their skyblock so that they can have better gear. (It is also worth considering to put new missions behind the tier walls) The rewards they receive would then inspire them to improve and continue to progress. And if they didnt have the right gear they would have to buy it from other players.

In a final note, I imagine the setup of these would be like an x-fil mission. There can be checkpoints along the way, but dying loses ALL items (this gives purpose to the "keep this item when dying" enchant). Completion of the mission or waves would of course grant a much better reward than leaving at a checkpoint (if completion yields 1 then checkpoint might be 1/4) There have to be consequences for losing because that encourages players to prepare.