Skyblock needs an economic overhaul/boost. Currently the top 3 players have over 1m in skybucks, which is insane compared to the next 11 players who have between 160k-100k, with the number falling very fast after that. There is no way to make money quickly and reliably, because challenges cap out at 100 replays with a payout of 100-200 skybucks each, meaning that fully replaying a challenge to the limit will only grant at max 20k meebles for either a lot of grinding. A solution to this issue that won't cause massive inflation would to add /c reset, which resets every challenge in the challenges tab, but can only be used once every 1-2 weeks.
Challenges also need revamped rewards, repeat rewards are fair as they are, due to some challenges being very easy to repeat, but items such as villager spawn eggs, which are needed to get a village working, are no longer obtainable, making even a small, slow, iron farm impossible to make, and more challenges impossible without other players help.
Another problem for the challenges is obtaining wither skeleton skulls, as they no longer spawn from skeleton spawners in the nether, and can only be found in a nether fortress (which don't spawn in the skyblock nether), meaning that there is a very small and dwindling supply of skulls that exist anymore. This could be fixed by either making wither skeletons spawn from the skeleton spawners again, having the skulls sold by the mobdb villager is SB spawn work spawning a wither, or by adding a shop that sells spawn eggs to be used on the spawners in the nether at a hefty price, but fair of $25k-$100k for a hostile mob (no iron golems).
Adding a vote-crate type system over the current weekly key can help the lower income players get a boost. This would work similar to the current vote crate and key, but instead of getting a skyblock key every vote, players would either have a chance of getting them every vote (1/10), out of the regular vote crate as a reward (10-15%), or lowering the time of getting a key from Corey to a day. Of course the items in the crate would likely need to be nerfed slightly, such as removing the Iron Golem spawner that caused the massive difference of the top 3 and everyone else, and replacing it with items of high value, but not economy breaking.
MCMMO also needs some slight fixing, by allowing players to get points for mining ores, and having the tree feller skill actually work.
Edit: Please bring back /is ms, just shorter than typing /island minishop.