Yeah that's weird, I remember someone suggesting Luffy was being "negatively influenced" by Usopp in that scene, like a naughty/bad influence lol, which could be why he reacted like that.
It always confused me that Luffy had no reaction to seeing Boa naked at all, especially when you consider this.
Zoro I'm surprised hasn't shown any subtle, ironically tsundere type attraction to Tashigi being a swordswoman and such a sword nerd, but I guess the Kuina similarities really doesn't help ofc? Trauma, grief and such?
With Hiyori, she's a legendary samurai daughter and they even ironically had an unintentionally intimate moment at least too, so once again I find it weird Zoro has no semblance of attraction to her.
It might be his sheer monk-like discipline or and maybe he's just asexual/aromantic, as he's shown no attraction to anyone at all regardless lol.
But I think he might still end up with Hiyori or Tashigi or so if they pursue him openly and actually get his attention and woo him lol.
I think either of them would be very compatible for him, although I love Zoro x Robin personally, I doubt it will happen. Oda has teased chemistry with her, Franky and Jinbei now and to be fair with her DF too amd being able to even clone herself, not even just her body parts anymore, she could ...WAIT I better stop there before this goes too far LMAO!
Seriously though, I don't even know who Luffy will end up with too but I doubt it will be Boa too for a few reasons. I hope Oda doesn't force relationships after the series ends but I do think the SHs will settle down with others at some point eventually.
Damn, I turned this into an essay/Ted talk lol.