Some of the mystique and great vibes people are looking for that originated from the original Ragnarok online is the open world/free roaming vibe of your exploration and leveling across maps.
Currently every map as you progress naturally through the game (Which in itself is forcing the player in a Theme park MMO design which is bad) leads you through corridor to small open zone, to corridor guiding you along a very strict and set path leaving you with zero sense of exploration and self gain.
Rewarding a player for smart play and exploration is something this game lacks, because of the forced theme park narrative and design there is only seemingly one particular area where you should be spending your time for any given level to gain exp/quest.
It would be much better if there were multiple options for X level character to visit, level and quest in - Which brings us to the point of the current gear/exp scaling making this not viable.
If you’ve managed to kill a monster that is much higher level than you, the EXP that monster gives is not static, it will be penalized based off your level if its too high or too low. This removes the option of players or parties to devise an efficient strategy/build to tackle these foes and areas.
Rewarding a player for smart play and decisive insight with builds/setup was something very integral to the success of Ragnaork online.
The current build/state of Tree of savior does very little to cater to anything outside of the very casual audience whom have little to no wherewithal to think critically in their choices.
The forced linear progression by level design and scaling enforces this motive.
Edit: Oh and untradable items is a horrid mechanic that only limits economic potential.