Cincy is just one of those cities that doesn't scream "hey look at me here is all I have." My best guess is that in Cincy you really just have to "know where to go." For nightlife, you have to know what clubs are hot and which are not. You have to know what nights are big where. In many bigger cities you can stumble out your front door and find people everywhere. I think that's how people get "bored" in Cincy from a nightlife perspective. Also, Cincy needs to do a better job including better nightlife "strips" where one can walk to 20 different bars all within a couple blocks that are all different and vibrant.
As far as other things, I dont think you can get too bored. There are plenty of cultural attractions, good sports of all types, shopping, etc. I am really not sure bigger cities have too much on Cincy in these categories especially when you consider Cincy is cheaper, no traffic, and more family friendly.