Suggestions

Allow wither to break blocks just like old times.

Make options to disable creeper explosions. Can be really deadly when afking.
Enderman stealing my blocks and placing them on place that blocks the water flow.. Allow us to disable enderman griefing..

We can hardly sell anything. There are too less items on shop that we could sell. Maybe let us sell more items like diamond/emerald/iron/gold/redstone/lapis/coal and many more.. Also the dynamic shop isn't gonna work if no one is gonna buy that item. Example if no one buys cobblestone it will be forever 0.10 on both sell/buy. Just make the shop all at fixed price. We need a fixed shop so eve.. See more

cus its a shortcut if its there

since an island can have multiple players in it, it would be better if the island had an /is vault
even if the storage for the vault is just 9 items/stacks. it would help a lot for skyblock gameplay :D

add a tool which can on right clicking a chest do
1. estimate a chest's contents worth
2. sell the chest contents
3. condense the chest contents