1) The game's economy needs a drastic rebalancing, at the moment the price for selling crafted items is far below the value of selling the individual components, meaning that there is no value in crafting for the purposes of profit (specifically to meet the debt questline). The best value for investment is literally fishing, as the fish are incredibly simple to get in bulk. Slave pricing is similarly affected, there's very little added value in training them for the purposes of reselling.
A good rule of thumb is that the value of selling an item should be equal to the cost of the components plus some markup percentage to represent the crafting time.
The same thing goes for quests to some degree, many of them are not worth the cost of purchasing the quest requirements, be they items or slaves, in order to complete them. Granted the favour is some added value but combined with the way the rest of the economy is currently setup it stands out quite a bit.
2) There's currently no way to directly leverage your charm for monetary gain, while the quest reward stuff can eventually come online to provide some extra value, it would be great to have some kind of profession which could use it more directly.
3) There's no indication during character creation as to which of the races has a unique class, the guesswork is rather obnoxious. A line in the race description detailing if they have one would be greatly appreciated.
4) It would also be greatly appreciated if there were some more starting class variety for the master. For whatever reason Harlot is not available, like it is for starting Slaves. This limits the amount of ways you can leverage your starting attributes.
5) This is purely anecdotal, so I'm unsure as to whether or not it has already been accounted for, but having quests be influenced by your gender generation percentages would be greatly appreciated. I played a game with 25% male slave generation and got something along the lines of 3 or 4 quests for male slaves. Similarly it would be good to have an indicator as to where Futanari sit on this spectrum, as they could be considered both or their own separate category.
6) There's something off about the smalltown shops. I've had a couple of times where I've sold stuff and not gotten the gold, and the shop doesn't always want to close meaning I have to go back to the main town, open and close the shop to get the window to close properly.
7) It would be nice to have somewhere in the quest descriptions for the "kill X monsters of Y type" quests that inform you as to where those creatures are.