Kursiv text? You mean like, a font change to make it look like handwriting, something like that? Yeah, that's not gonna go through - even if you code it, it won't show up right for people who don't have that exact font on their computer. It might even shift to ugly little blocks, instead. :/

I've found that my biggest issue is with the spacing - seems every time I post fic on either site from my word processor, it either makes these huge, ridiculous gaps between paragraphs or nukes the spacing completely. I usually fix it manually, but in cases over even just ~1k words, it gets really annoying, fast.