yogibooboo
Rav Falk has no objection to housecoats with slits IF you’re only around immediate family. His concern is that a woman will answer the door or welcome guests, in which case the slit is not permitted. What is wrong with that?
Also, he says that eyeliner be applied with moderation (I’m guessing he’s trying to discourage the really thick, trashy look) and he DOES NOT forbid it. But, yes, l’chatchila, it should only be applied moderately.
Regarding the hair- He says its preferable/recommended that the hair not hang loosely if its longer than shoulder-length. This doesn’t mean that you must tie it together completely (pony) and it certainly doesn’t mean that if you feel you can’t commit to that, it’s ossur!
Regarding every topic in the sefer, Rav Falk clearly states the halacha in addition to the recommended practice. Obviously not everyone can follow these recommendation, and certainly not regarding every issue.
I don’t feel I am up to a level where I can follow his sefer to a t, but at least I don’t discredit or misconstrue the whole sefer.