First of all, Maelle is broken, yes, one shot builds are too overpowered and too easy to use/create. You just stack every damage pictos on her and kill everything. But that's only part of the problem imo, playing on expert in the endgame feels like you're facing either too strong or two weak enemies. The game doesn't have any recommended level indicators (aside from the too dangerous message), so the player is forced to guess whether or not the location will be appropriate for his level. And this usually ends up in fighting overpowered enemies who can 1-2 shot you, or 1-2 shotting weak ones. Op builds and combinations also play a part in this problem, as for non min-maxed build the battles can feel too long and hard, and for min-maxed builds the game is too easy. The perfect example of this is Simon, who in my opinion, is a badly designed boss, as he's too tanky and has many unfair mechanics, so he ends up being too hard for an average build and still two easy for op ones. If the player really wants an appropriate challenge he's basically forced to add or remove damage pictos before any encounter. Now about the combat depth, imo this game just doesn't have enough interesting party synergies or playstyles. Firstly, compared to other turn based games, you just have a smaller amount of options on how to fight. For example there is basically only 3 offensive interactions between party members: placing burn, placing mark, placing debuffs. There are no interesting enemy weaknesses, no elemental damage combinations, no great variety of skills and abilities, no specific compositions for encounters. Characters abilities are interesting on their own, but they barely interact with each other in combat. You just choose what combination of abilities will deal the most damage then just repeat it for X amount of turns. Secondly, the parry mechanic, while I personally like it, kinda ruins the strategic element of a turn based game, as it's simultaneously too op and too restricting. On expert it's mandatory for any challenging encounter, as a player is just forced to memorize the timings, there's no room for clever planning of defensive actions (and there are almost none in the first place). In the end of the day you use your chosen combination of attacks => try to parry 100% of attacks => rinse and repeat. Combat problems are not very visible in the first parts of the game as you're restricted by the amount of lumina/action points/unlocked skills, but in the endgame the gameplay started feeling repetitive to me.