Fan service of the sexual kind is everywhere now and I'm just so tired of it. It's become like modern pop music, where most songs being played on the radio have suggestive lyrics and not so subtle sexual innuendos. It's usually also very unbalanced, with female characters both being portrayed as sexual objects but also stripped of their power and Independence. But when it comes to male characters, they're shirtless at best, which isn't necessarily objectifying nor degrading like some female costumes tend to be, and they're still shown to be powerful. This is most likely because it is assumed that most gamers are straight men (and honestly, I think it's insulting to assume that straight men in general are this simple minded and need to be pandered to in this way).
But there is a vocal minority of guys who get very upset when developers decide to put more clothes on women (because we all know that if they wear as much clothes as the male characters, they have to be burqa wearing Muslims - at least if you believe the rhetoric of the people who identify with the ridiculous and non-ironic hashtag "bonerculture"). The other day I read an article about people being up in arms over not being able to grope women in Dead or Alive Xtreme on PC. Just looking at these ridiculous female character designs isn't enough for some people. There's also been some backlash against Mortal Kombat 11 because they've made a conscious decision to put normal costume designs for female characters that are on par with those of the male characters, because the series has a growing female fanbase (and also more female members on the dev team). Imagine being upset over not having your female fighters dress in string bikinis and having silicon boobs. I've also seen people complain about Aloy from Horizon Zero Dawn not being "fap friendly", or that Ellie from The Last of Us is lesbian - and this of course means the game is "feminazi and SJW propaganda" and thus unplayable. I can't help but dismiss everyone who makes such stupid remarks as basement dwelling incels.
To me, the fact that more women and minorities are playing games and that developers take that account into their design philosophy is something to celebrate. This doesn't mean I am opposed to characters with sex appeal or nudity, but it doesn't need to be everywhere and when it's a thing it should apply to both female and male characters alike.
As for non-sexual fan service, I do enjoy the occasional nod to previous instalments in a franchise. Using Mortal Kombat as an example again - in MKX you could unlock outfits for characters like Kitana and Kung Lao based on their MK2 and MK3 appearances. They look super cheesy, but it's fun to see them rendered with more realistic graphics. Or the old classic PS1 era polygon Lara Croft outfit in Rise of the Tomb Raider. That's fun fan service, imo. Another example would be how you can listen to soundtracks from previous games while driving around with the Regalia in FFXV.
Of course, some games rely very heavily on nostalgia fan service but then you know what you're getting yourself into. Kingdom Hearts, World of Final Fantasy, Marvel vs Capcom etc. I see nothing wrong with those. However, I do think KH ignoring its roots is worth criticising. It was originally pitched as a Final Fantasy x Disney experience. The FF characters weren't just minor fan service. They were a huge selling point back in the day. To just drop them now feels like a disservice to those who've stuck with the series since day one.