3 things
1) The Monster Girl question: Mermaids. I'm honestly surprised that there hasn't been a contract/side-quest yet that revolves around mermaids. Once I arrived at the port for the 1st time, I could see Mila having to chase down a horny sailor who went AWOL for trying to get some mermaid tail.
2) 5.0 will only have 1 half of the last chapter. How would you end it? I assume that there will be a message that says: "Thanks for playing. Plz, wait a little longer so I can finish the ending." But... what would be the scene? Is it before the final dungeon or the final fight? A moment when a character discovers a revelation or when they found their resolve? Or will it end on another cliffhanger like the last chapter?
3) It has always bugged me that don't get anything for beating Dorian early. I would understand the issue with balancing the difficulty if the reward IS that powerful. But my response is like "Yeah, but if the player faced an impossible-to-win boss and still won, why not reward them for doing the impossible." However, since there's apparently a story reason, I guess I can let it side. And besides, since you tackling the issue now, I'm a little late to make that complaint.