Good afternoon, these are some suggestions for things that could be improved or changed based on what bothered me/happened during my playtime.
You might like some of them, not others, and some might already be there and I just don't know about them, haha.
Armor Shards (Any of these options can make obtaining/upgrading armor less tedious and also help decongest areas, since most players use low-level zones, ruining the progression/experience of new/lower-level players.)
_ Add the possibility of Tier 3 (like Emerald Regen).
_ Change the Shard drop rate based on the mob (higher level/difficulty/tier, higher drop rate).
_ Add prestige to Shards (to obtain more).
Armor
_ PvP or some other use to motivate/make it worthwhile/necessary to upgrade armor, since otherwise, having Diamond/Nether armor is more than enough to complete any role.
IS
_ Add a minion/armor stand/item/statue/etc. that functions as an "AFK" player for the island and generators. (It can be purchased, obtained with keys, through random drops, etc.). The idea would be to avoid having to spend PC components, electricity, etc., to generate income while away from the island. Furthermore, while playing/progressing, players generally don't want to spend hours on the island just to earn money, as the goal is for players to play and progress, not remain static on the island.
To add more difficulty and choice for players, it could be implemented like a selling wand, but in reverse. (For example, it could start at 0.25 and require upgrading with currency to reach 0.50, 0.75, etc., giving players the option of remaining AFK or keeping the lower-generating item until it's upgraded).
_ Island size limits for 3 to 5 players (This reduces resource consumption since the island has a size limit, resulting in better performance because there wouldn't be as many islands. It also helps attract more players since you can play with your friends on the same island and progress together).