When you unlock more dangerous enemies and weak items you make things more difficult for yourself. Unless you plan your upgrade path with wiki you can get unlucky and complete half the game unlocking weak items with a low level bank, bazar, no witch and 1-2 altars as your gold income steadily decreases until you clear purist GT. (which you easily not find out about if you focus on a few dungeons)
A "progression" system where you have to manage your resources is not necessarrilly a bad thing but the kingdom presents itself as a puzzle hub/"progression" dealer, not as a campaign at all and doesn't do things that you'd need for a management campaign like telling you what things do before you buy them. The more you play the less gold you get from trophies and the harder quests get so if you're not making your upgrades count you can get bogged down. The set up at the moment makes things even even harder for bad players and its also possible to make things even easier if you already know what you're doing with the right unlock order or even just ignoring some unlocks altogether.
The end result is that half way through, the game drops this responsibility on low win rate players to play better, farm or play another game, because in the future there's less gold, not more, after lulling them into a false sense of security with stuff like the bank vault size upgrades making it look like your rate of gold income will greatly increase as you play. This was annoying but not a huge deal initially: I had to farm and play less carelessly than I'd like, and start worrying about my economy, in what I thought was a puzzle game. That's not so bad. The problem is that 10 dungeons later there is no indication whatsoever that you get flaming, pqi, 150 gold trophy price fix exist at all: it looks like your gold income is just going to decrease forever. I went on the wiki, found out about those things, reoriented my perspective on the campaign as managing my gold to avoid having to farm, but if I didn't find something on the wiki I was ready to write the game off as ruined by an annoying campaign. And if I couldn't/wouldn't enjoy playing better, I would end up in a downward gold spiral and stopped playing.
It would be better if there was a big neon sign saying DONT FUCK THIS UP OR YOU'LL GO BROKE at the start of the game (or equivalent) but before that I just don't see why there's a way to lose the campaign in a funny puzzle game or why you'd ever make the game harder for bad players and generally why there's a gold/locker management side of things at all. The campaign is basically a roguelike, it's really restrictive, it doesn't tell you what things do, and you can do permanent damage to yourself, but despite a lot of cool/funny writing, stories, set pieces and stuff management doesn't fit in to a story that's 70% humour, 30% awesome ideas/set pieces 0% plot. When your prices start lowering you can't engage with it as part of a story 1 because you aren't told and 2 it's totally at odds with the tone of the game, so it can only seem like an inconvenience. Does anyone actually enjoy worrying about gold? What is the design reason for it to be there?
And no, (inb4) farming gold isn't the same as just playing the game. If I'm doing something to get gold to do something else, I'm not doing what I want. Yes I could be serene about this and enjoy it, and enjoy my enjoying of it, and that is what I plan to do, but it's still bad design.
I'm mostly good at complaining about things but here are my ideas to make kingdom management less annoying.
Enemy unlocking should be transparent/ should be restricted to only a few zones with random monsters with other zones drawing from their own pools that ignore monster unlocks/should increase your gold income somehow if its a tough monster (all of them except the goat)/just have all enemies unlocked from the start and tweak however needed to fit that in.
Quest reward items should let you know what the items does, its cost, and its size when you hover over the items on the quest or adventure screen.
It should be possible to see what the 3rd level of upgrades does before taking the 2nd level upgrade to a building. Bazar level 2 upgrade should be made easier.
I don't really remember the bank quests but I vaguely recall the level 2 or 3 quest being either too hard, or too hard to get assigned.
Witch should have a (maybe smaller) chance to spawn anywhere or in a variety of places covering each path.
God subdungeons should have a (smaller?) chance to spawn in any dungeon you've already found the god of/you should know where you have to go to get them
You should be told that unlocking more gods gets you more altars.
You should be able to prepare and veto any item you've carried out of a dungeon ever.
You should be able to save default vetos/preparations for each class with exceptions for race if you want.
Consumables should be "recharged" if you prep them and win the dungeon (not sure if this already happens I don't remember how that works.)
Viper wards and soul orbs should only appear in shops if your character has the appropriate immunity and if there are enemies with the ability.
As you unlock more items you should unlock more shops per dungeon/you should unlock shop rerolls per dungeon that you could use on unwanted items.
Trophy decay should just be deleted or the narrative should be revamped so it feels like part of a campaign rather than a questionable design decision of an inconvenience.
Unrelated ideas but while i'm here:
maybe if the boss is bleaty, you should get a warning without having to scout him. Maybe also meat man, tower of goo and is there a magic resist boss? Ones that can require a different approach which it can be too late for if you find them late.
Retaliate fireball on wraiths/goos is brutal. I don't think fireball retaliations should apply on hit effects. Or those enemies should just be made an exception and ruled out for gaan talet. Bloodless bleaty on VGT if you're a vampire should definitely be made impossible.
Also why do specific god preps even have penalties? Some of them are fairly light, some of them are really harsh, all of them are a hassle. why is there a sacrifice to guarantee a shot at a certain approach? If you really need a certain god to clear the dungeon there's no guarantee that the approach is gonna be good enough with the penalty accounted for and you can just scum for the spawn if you're using it as a problem solver. If you're not using it as a problem solver: you just want to play a dungeon a certain way, the penalty is just annoying and serves no purpose. I'd much rather they were more expensive than had the penalties. If they did lose their penalties they should lose their close spawn or again be made more expensive. You could also have different tiers of devotion with different effects.
Gods should list their likes, dislikes, punishments and inital piety should be listed where their boon descriptions are, if you haven't got a boon selected. I have the wiki page open anyway, save me some trouble. Taurog's ability to punish you for converting an item even after you leave should be mentioned on the boon description.