Well, the title says that the MC is the chosen one of a goddess and both the description and the early part of the game confirms that he was chosen and he was given an extremely important gift. 95% of the time this means a power fantasy story and another 4% is about an MC who has to come to terms with being awesome. It is not unreasonable if someone were to assume this story would follow a similar path too.
But in contrary, at least as i see it, MC is basically the "weakest" member of the cast and even a lot of regular human girls like Katie are more "powerful" than he is by the sheer virtue of them being f-ing rich. If anything, his main power has been his honest, good heart, since most adversaries he faced so far have been desperate rather than evil.
Again, the way i see it, you never deceived the player or falsely advertised the story to be something it isn't, but the fact that you didn't follow an overwhelmingly common path does mean that almost every player who comes with normal and natural assumptions will have a moment when they realize that something is not going the way they thought it would. I had this moment too, i was just not active in this thread back then.
Fortunately for me, i didn't really pick up this game to see the MC using powerful magic. My favorite part by far has been the bowling party because it was just fun, connected a lot of characters (pun intended) and gave me a small but optional challenge to figure out who is who without being forceful about it. Creative and funny magical shenanigans can usually win me over and this helped me out a lot when it came to rewiring my expectations.
....what to do..or where to go...???? 
