Oh, me too. I mean I also try to write it as though it were subtitled, if that makes any sense. Like, my fic is written to be a translation, not what they're actually saying, so I don't necessarily bother with "ne" and the rest.

I don't think I'd be thrown by seeing "aaa" and "oi" in a fic, though.

Also, this would get doubly confusing if I ever ended up writing fic for anime/manga set in the US.

(Yeah, I love Hiro and Ando's subtitles. And they move around the screen helpfully! -- Which will suck for vidding, sigh.)