I'm just going to go with we're not going to agree. Honestly, I'm surprised you came back for the second game considering how inconsistent the romance routes were in the first game.
As for your other question, from an earlier post from myself, you can hit all the routes without a NG+. I can't tell you the specifics, but I do remember getting all the CGs and the harem end by reloading my save and I definitely did not bother doing a NG+ despite doing one in the first game.
So, to confirm, there is in-fact a harem ending? That was my main concern, if I'm honest. Because in the first game, in order to get an ending, you needed to go through 3 dates with one character to get their specific ending. And the fact there's clearly multiple love interests doesn't automatically indicate a harem ending. So that's why I was holding off on the ball game date with one of the 5 I can choose, as I didn't wanna inadvertently lock myself into a specific route. I had no problem doing it on the first one because I didn't even know that there's were prerequisites to an individual ending. All I knew was I wanted to be with Satsuki Saijo. Her attitude at the beginning made me set my sights on her. If I were to do a second one, I'd likely go the Konoha Jinguuji route. But Satsuki honestly captivated me. But I digress. I appreciate you letting me know there's a Harem ending. And the dates are just filler. Not essential.