I don't like fan service or sexualised content when there's nothing else to go with it. If its part of a larger product and isn't really the central focus of the product then I'm cool with it, I'm an adult I can see something a little racey without my mind being blown. My touchstone on this is Game of Thrones (GoT), it includes massive amounts of boob and sex ... well south park kinda nailed it. But for GoT it comes as an addition to a massive story, complex characters, amazing fight scenes, incredible sets and just everything that is amazing about GoT. I can watch GoT without it causing me to have a conniption fit so yeah I'll be cool with most things.
If FE:Fates is literally all about the my castle stuff then that would bother and disappoint me, but so far the fan service seems to be not part of what i consider the bulk of the game and in fact much of (but not all) the fan service seems to be optional and what I have seen so far doesn't seem to be outside of what other games have done in the past to varying degrees.
So yeah, some bits im ok with, other bits I'll live with.