My list of suggestions

Integrate the community into getting things done on the server
Allowing, people to add their ideas, is the first step.
Many people asked for an improved loading-screen atmosphere.
I'd suggest using the art of the people that compete in those Forum-Side-Events for example
But now, let's cover up my points:


STORAGE / INVENTORY / SHOPS

- Make purple and green potions overwritable
improves the quality of life

- Make items stackable / droppable / storable

improves storage place cleanliness and with it, the good ol' quality of life

- Give players the opportunity to use 2-3 store box slots

reduces the amount of unnecessary created accounts and/or characters

- Increase the number of placeable shop-boxes

reduces the amount of created accounts

F5 HUB / OVERLAYS / VISUAL-STUFF

- Make the F5 Hub better visible

a lot of players (me included) didn't/don't know about this feature

- Add the Forum / Discord / Webpage To the F5 Hub

makes it more versatile and fills up the corresponding media

- Add countdowns to the corresponding missions (Stable boy, for example)
currently not functional (shows "no time limit" at the horse mission for example)

- Item Mall - Pictures/Showcase needed

improves the visuality of sold items -> which increases the amount of sold items

- ShopBox Hub is mostly overseen -> Make it right-click functional on the item

reduces faq in the long run

Feel free to write constructive ways of improving my list of possible improvements.

- Djihad

EDIT:

Fix F5 Wiki
Doesn't work properly when typing in the names and the grade of the item, yourself.

Fix the random kicks
No, it's not an overall metin2 problem

Edit:
Regulate the bad/good drops
Find a solution for the excessive drop of carrots, hay, ginseng, and whatnot.

Make Costumes tradeable
I don't know why there's a barrier

Improve the Item PickUp-Filter
QoL

Fix the visual bugs on shamans
Confusing, PvP advantage

Fix the "visual loss on death" bug
Puts you into disadvantage