I think what makes players grind is that they get focused on a single girl and try to go through all their content while ignoring the rest of them. I'm guilty of doing the same thing in other games. With AFV, it can get pretty grindy if you play it that way.
The way a developer thinks players will play the game can be very different than the way players actually play the game. In a lot of games each girls development branch is completely separate from the other girl's branches making it possible to do the entire branch without even saying hi to the other girls. With AFV, in my naive attempt to minimize grinding, I made their branches very much intertwined. My thinking was that between all the girls, there will be enough content going on all the time to keep players from having to grind too much, but what commonly happens is a player will get hung up on a girls progress because she can't progress anymore until another girl or storyline progresses to a certain point, and just keeps going through week after week trying to make something happen that can't yet.
So my advice for the most well rounded AFV experience is to keep all the girls in mind. If you're hung up on something, go explore the rest of the locations at different times of the day and something is bound to happen.
