I disliked him in City Folk, which I played for a hot second (less than an hour, I think). I didn't like playing on the Wii, and I was very put off by the fact that the first thing that happened in the game was I was made to get a mortgage and then had to sell items to the person who gave me the mortgage in order to pay it back. I started playing New Leaf because I thought it was research for my last job (turns out they meant Pocket Camp but they just kept saying "Animal Crossing" so I assumed) and got very into it. I don't dislike him as much anymore, and divorcing him from the store definitely helped with that. I do agree he doesn't have much personality.
I think his fandom for KK is cute, but I also am really bugged by KK--his nakedness, his voice, his "cool cats and kittens" phrasing so...
But anyway, moreso than a businessman, I think Tom Nook is supposed to be a
furusato, a traditional Japanese village role related to collective debt, which makes sense when you think about the way investing in the island works. (I really like Ian Bogost's essays even when I disagree with him.)