We-ell, actually I like Molly and Sally. My problem with the female characters is that they are way too tertiary and one-note--I blame that on the writing more than the actresses, though.

Molly needs more combative scenes with Sherlock (I love their "you gained three pounds!" "two and a half!" exchange) because it shows her backbone--and she's obviously smart if she is the one giving Sherlock permission at the morgue (as opposed to talking to her superior). However, I think Sherlock acts towards her exactly how he would act if she were a man--manipulative. Also, if you've read her canon blog, it shows how adorably silly she is. Personally I think it's a bit too silly to the point of caricature (like Kelly from the Office) but I don't think that doesn't make her a fun character, if only they would do more with her.

Sally is fun, but again, one note. She just acts perturbed at John and pissed at Sherlock. Give her more emotions! I loved her little nudge to Lestrade when he said, "Well don't commit suicide!"

Meanwhile, I'm worried Irene will be shown as "cleverer than Sherlock" by making Sherlock go all mad for her. Moffat likes that power dynamic in his hetero relationships. Personally, I would think that if we got Sherlock to merely respect Irene it would certainly show how important she is to him (as she was in the books).