I don't think the author of the blog is doubting that there are strong female characters in fantasy. What she doesn't like is those strong female characters being portrayed in cliche'd fantasy roles (the whole water vs fire thing, the men going out and being men, etc).
I'm happy to say I unintentionally broke one "women's fantasy cliche" in my NaNo. Okay, yes, I did have the male pyro kid, but his mom was an earth mover. *gasp!* NO WAI, says you. YA RLY, says I. She liquified a gargoyle statue and sent pieces of it shooting out like stone bullets. Yet she's just a regular mom, with a 9 to 5 sort of job. Cheerful. Smiles a lot. No navel gazing for her - okay, bad guy destroyed, time to go home and eat dinner. What did you do at school today, honey?
Personally I think that blogger needs to delve a little deeper in fantasy. By no means are all women weak in fantasy, nor are they all cliche'd in the way she talks about (and if they are, there is a strong point about them to counter it, I promise). If she's making such broad generalizations then she has obviously not read too far into the genre, or she has personal blinders on that allow her to pick out every cliche'd female in every book yet skim over or ignore those that aren't cliche'd because she's still pissed about the cliche'd one that appeared in chapter 4.
Some points I could see and agree with, but to me it just sounds like she's not picking up good books or is going into them with a pre-formed opinion. Time to branch out, methinks.
Or maybe I just have good luck picking out books. I don't know.