I didn't assume you don't like anything fun or colorful. The best parts of P3 were the parts that aren't cold, they are the social links and the characters and personalities that move past that stuff. Atlus continued moving in that direction with Persona 4 and completely shed the shell of the grimdark self serious past games, and boom, it was hugely successful. #FE is another take on that style of evolution. Obviously it hasn't been as successful, but I never argued that in the first place.
I argue that fanservice is just fun content and is incidental, not a cause or incentive or some strategic (from your statements, I'd allege you're reaching conspiratorial) bullet point on their design docs. #FE is pretty tame compared to 'bad anime' stuff out there. Fanservice shouldn't just -not- exist. There's plenty of stuff in the Vanilla P4 that people would call fanservice that I think add a lot to the game, lots of memories, lots of laughs, stuff that add personality. I'm not going to defend the increasingly sexual fanservice because I know that's a whole other bag of worms, but I think dismissing all fanservice is missing the point and is just grouchy old-man-shouting-at-cloud tier stuff.
On the last point, it's not really surprising that 'waifu discussions' are the most visible. Waifu posts are the easiest, most surface level shitposts to make because the games are most memorable for their characters, and most people who played the games do end up having favorite characters. The internet LOVES easy shitposts. This phenomenon shouldn't be propped up as an argument against a game.