I'm glad to hear you enjoyed the game!
For your peeves:
1. There are going to be demi-human girls added to the main cast. I have at least 2 completely new ones planned for the future. Iris and Chloe (the lizard girl and the mantis girl) are also demi-humans, and will be both getting a full story in future updates.
2. The isekai thing. I can understand it feeling a bit superfluous. Personally, I have gone back and forth on its inclusion in the game. (I considered making the MC actually from a very rural, human only village, and maybe Rei could be a spirit that's attached to the inn). I'm mostly using it as a literary device at the moment; to give a reason why the MC has no knowledge of this new world, and needs explanations/makes mistakes a modern human might. I will be getting more into the "main story" in the future, regarding the Goddess, Rei, and the future of the game world.
3. Yea...the stats. I guess it could be considered unnecessary. I tried my best to make it as non-grindy as possible. From my experience (though it may be skewed a bit as the one who actually made the game) just doing odd jobs on time slots where you have nothing to do, and when trying to make money, will generally get the player past most stat checks in girls' storylines. I was kind of going for trying to make the player feel like they are actually interacting with the world, not just cruising through disconnected stories. In the future, I hope to add various art and art variations to each workplace, to reward players a bit more for grinding stats and money.
I hope that explains my reasoning a bit, and thanks again for checking out the game ^^