Having spent a long time in the game, I have a few suggestions.
1-) Daily login bonus to the game, event etc. In order to direct the player to the game, even small gifts can be brought.
2-) Clan / guild or group system can be introduced.
3-) In order to prevent unfair item transfer, we should be able to shop in the market with the minimum and maximum price determined by the game for each item (For example, the dragon butcher sword; The minimum price that can be put into the market determined by the game is 30,000 gold, the maximum price is 100,000 gold, even if this order is I think setting up a market should be brought).
4-) If you have reached level 50 in the game and you have finished your missions, there is not much left to do. In order to have a better quality and fun time, daily access to the dungeon or personal leader style individual events can be brought.
5-) Some of the items in the merchant are only sold for diamonds. It would be better if we had the chance to buy them with gold (1 Dragon Butcher's sword was around 6000 diamonds, I think a lot).
6-) Prizes can be rewarded more in PvP mode (It was very sad to see 15 - 20 gold after you kill). The incentive to play PvP should be increased.
These are the things that come to my mind for now
I am using the translator, I apologize if there was any disagreement. Thank you for your time and reading.