Biggest issue with this game is the utter tedium of the last part of the game, where you basically have just the Darkest Dungeon (and I guess the blood court now) to clear out. It is such a fuck you grind to get through all of the DD runs and claw through the court that I gave up, despite my groups cutting through it without casualties or major incidents. Up to that point, the game is consistently challenging and rewards tactical play against the various bosses (and their leveled up versions) and the spelunking grind is fun.
Other issue is that there are four classes that are god tier (Shield Bitches, Berserker Bitches, Graverobber, Jester), three you need to nearly always have around (at least one) in every group (Cleric, Musketeer/Arby, Occultist) for healing and CC, and a bunch of "I hamper myself if I take these guys" classes. Seriously, my Cleric, Jester, and 2 Shield Bitch group just bodied everything in the game on my last playthrough. Reason is that those classes all do their function in any position and can drop DOTs in addition to damage, while the three heal bots all bring some form of utility that makes the others better (Stun for Cleric, Mark for Muskie, Pulls for Occultist) at raping things. They can also hit any position in an enemy party, which is the major thing holding back a lot of classes that would otherwise be standouts (Crusader, Bounty Hunter, Abomb) but turn to shit the second someone gets moved around (or the critical target is buried in the back). I get that some classes are supposed to stink (Antiquarian), but for all their tweaking the class balance is terrible. It makes the grind problem even worse, because by the time you get to the point of hitting the final dungeon and countess, you don't want to fuck around with fun combos anymore and just want to win and get it over with.
That aside, the first 90% of this game is some of the best turn based RPG party management game I have played. Its worth the purchase for that part alone, even if you never beat it.