This game is heavily dominated by whales (people who spend lots of money in addition to time). The publisher of the game also cares very little about player experience and gameplay quality.
One issue is the implementation of the FTG system (energy that you need to run dungeons and nests, replenished daily and in hot springs).
Before reaching level 95, each dungeon costs 60 FTG. After, each costs 5 times as much, at 300.
Here's a problem. The main quest currently spans from chapter 1 to 17, and it is not possible to finish all 17 chapters without reaching lv95 from the experience from main quests. This means that for the remaining chapters after lv95, you have 3 choices:
1. Use the "skip" feature to jump to chapter 17 and miss out on all the rewards in between (permanent title/stat bonuses, gold etc.)
2. Persevere and finish the chapters quest by quest and drain all your FTG without achieving much else on your lv95 character, and enjoy the lore (which, at this point, is less immersive animation &storytelling and more black screens with plain text)
3. Ignore the main quest and have a portion of the endgame inaccessible (Red Lotus, which is only accessible if you advance or skip to chapter 17)
Because of that, players have to already be thinking about minmaxing (title stats) before reaching level 95, which is highly counterintuitive gameplay.
Lore nerds can't enjoy it because the NPC quotes have horrible translations and aren't proofread.
Completionists can't enjoy it because some side quests are bugged, and publisher's fixes to them are whimsical stopgap measures (asking for a quest item to complete a quest must be done through Customer Support and isn't 100%, even though the quest item not dropping is the result of them changing the drop tables without also updating the quest).
Another problem I have with the game is the class balance. The obvious power disparity aside (Vena Plaga being overpowered with super armor and many i-frames), there's also an economic difference between the classes. I'll explain.
Jelly beans are a valuable endgame resource used to prevent weapons/armour from breaking when going through the enhancement process. These jellies are bought with real money, with gold from other players via Auction House, or rewarded via side quests. Here's where the classes differ. There's a particular chain of side quests involving a romantic NPC couple named Lucifina & Rodain.
The starting class impacts your quests, including this quest chain, by turning the character classes you didn't choose, into NPCs to fill roles within the narrative. Certain cutscenes and storytelling perspectives are made unique to each character class. As such, in a party, the game resolves any class-specific cutscene conflicts by telling the player to run the dungeon solo or the quest will not activate/proceed (which is a problem of its own, an MMO that discourages multiplayer).
Because the game's writers try to forge story perspectives unique to each character class, the Lucifina-Rodain quest chain differs in length between the classes. Clerics, Warriors and Sorceresses get 7 quests (100 jellies per quest, totaling 700) while Archers get 9. For newer classes like the Assassin? There's no quest at all because the writers forgot. No jellies4them.
All this is in addition to the myriad bugs that go unaddressed(disconnecting when attempting to enter a dungeon will strip away your character's MTX, pets remain dead and unsummonable after horn of life revival, talking to an npc in a dungeon right before a scripted cutscene softlocks the game etc.), pay2win advantages (though this has been dialed back) and bad customer support. We haven't even discussed LOOTBOXES