just found a link to this thread, hope y'all don't mind me reviving it!
sailor moon was my favorite cartoon as a middle schooler and i still relate to it sometimes. i think i learned a lot from it and carry a lot of its associations with me still
i think michiru is an F too. it's also a gut feeling, but i'll try to analyze it.
for one, i think you can see it in her violin playing and in her painting. her playing is always expressive, moving, usually has an underlying sadness to it. what i'm thinking is that i play music and my brother plays music, but we play for very different reasons. obviously, we both enjoy the sensory aspect of hearing music, but we are very different players as well. he's much more interested in music theory, in emulating the great musicians and improvisation. he plays because of the engagement of thought. i'm much more interested in the way the music is linked to emotion, in interpretation, and in expression. i like the way it allows me to express feeling. accordingly, he's a T, and i'm an F. and michiru seems more of an F player to me. in her paintings, too - notably the one of a whale jumping out of space surrounded by color, and the one of the destruction of the world - they seem inspiring and despairing, respectively. and both appear loose, colorful, and dramatic. nothing is overt; it all hints at F.
she does cover up her emotions well, but sometimes you hear them spring forth, and when that happens, they're astoundingly deep. like right around the time uranus decides to take her henshin stick - first michiru yells at her not to take it, because it will change her life forever, and then dives in front of uranus, unthinkingly (haha, that word choice was not purposeful, but it works) blocking her with the arm she uses to play. and then she kind of blabbers to haruka that she'd been stalking her because michiru knew haruka was "the one", and always daydreamed about riding by the beach in her car.
michiru also makes comments about emotional honesty from time to time. i think it's easy to suspect she's T because she seems cold sometimes, but one, i've seen this explained by her not liking people being fake (Fi), plus in terms of praise, she's dealing with the fact she won't be able to fulfill her dream of being a violinist because she has to save the world - which includes hurting people and potentially sacrificing herself. and while michiru holds fast to this as a hardline rule, i think it's very much an ethical decision - she's choosing the greater good. haruka and pluto (also T) demonstrate angst for this too, but not nearly as often. she also often laments how she may have to hurt people, which haruka (definite T) only indicates once, and only by staring at her hands - in response to which michiru says "i like your hands." additionally, when her and haruka chat with others, michiru often plays the more supportive (good cop, lol) role - praising or comforting. at one point she says to usagi you should "cherish" your first kiss - then overtly gazes at haruka - and after laments that she and haruka don't have luxury of falling in love... flirt bait which haruka totally ignores, lol
the only evidence i would give to the contrary would be when she raced with ami. though first, michiru notices that ami swims "vibrantly" - not really a T kind of assessment. then she got really into the competition of it. she was upset that ami didn't put her all into it, annoyed that maybe ami was trying to make michiru feel better about herself - and that's not a particularly logical conclusion in and of itself. michiru had never met ami before and unfortunately ami was already feeling down that day... and once haruka points it out, michiru feels bad about it.
but add that to neptune being the soldier of "embrace", type O blood, and a pisces...
the most convincing thing of all, of course: haruka remarks that michiru "can't even kill one bug". lmao
