Mabi has a lot of old systems that need to be imrpoved and adjusted urgently but I think com the bat is one of the crucial ones. tbf, the combat system was fine until Nexon started mimicking the FF14 combat system and they only copied the bad stuff from it. I have to admit that, the fairest boss fight with the new combat system has to be Girgashiy. Excluding the fact that it can die in 5 seconds the moment he kneels, they are lots of good elements in it: 1) easy mechanic 2) combat is readable and can be dodged and 3) no adds. Then, the rest of the bosses exist just to annoy the players.
Let's talk about some annoying settings about the boss fight
Healing: Succubus Queen and Fluer will heal around 20%~40% when you fail the puzzle. We are not talking about 5%~10%. The healing is already insane then you have unlimited adds to shot you to death and the dps debuff will only extend the boss fight even longer.
Adds phase: Admiral's Lingering Spirit, a boss that has pretty decent mechanics but then the boss fight gets destroyed by the adds once again. In Admiral's Lingering Spirit's fight, the rats can each deal 200 damage hit with fast movement speed and high attack speed. Then you have 20+ rats, flying swords constantly stun players with lightning, and Admiral will desummon your pet after the dark clouds part. In a game that the tank role is close to non-exist, it is very unsatisfied.
The G26 boss fight was awesome until the moment they added adds in the final boss fight again. Their reason was, "we didn't expect that so many players to defeat the boss in the testing server so we are going to increase the difficulty."
Mabi combat system is failing because they don't provide players an opportunity to most of the attacks. In the FF boss fight has a set of routines to memorize, a single-target attack, an AOE attack that the ranged is shown, specific attack that can be dodged/share damage by reaching certain requirements. Mabi doesn't do that often in the latest content. For example, for the Feth's Gate, you can't predict which side the gate is going to shoot, you can barely dodge the attack (especially when you don't live in the US), there's no attack pattern you can remember... etc. The boss should indicate that what skill it is using, the range of the attack, and the attack countdown timer. Therefore, the players are allowed to dodge. By just adding these indications, it is fairer to the player and people might be more willing to do the newer content.
It's sad that Mabi could have been a great game. the gacha fashion is a lot better than other games, there are lots of interesting interactions, the story has been way better than before (they should just wipe the entire Shakespeare update)... But at this point, Mabi has way too many problems to fix or maybe even beyond help at this point. Like, Nexon seems to balance the contents based on reforge system, there is a lack of in-game progression (insane low materials' drop rate that makes the majority of the player base get stuck in mid-game), ridiculous success rate (anything that is below 5% is lunacy, especially when you can fail on 99% success rate very often)... etc Nexon doesn't really care what players think unless the KR players strike again. I guess we can just go back to afk until the game is dead.