"A yoetzes course of study cannot hold a candle to years (or more!) of immersion in serious learning."
R Alderstein doesn't seem to have any idea how rigorous the course of study for yoatzot is. But leaving that aside, he seems to be saying that a yoetzet simply don't have the level of learning neccesary to give an accurate psak.
I am absolutely sure that he's not suggesting anything so blatantly sexist as the idea that women don't have the necessary intellectual skills to master the halachot. So it must be that he feels that studying for smicha itself, and the actual conferral of smicha, is what makes one truly qualified to rule on taharat hamishpacha.
Therefore, I am left with only one conclusion. Clearly R Alderstein feels that the yoetzet course is insufficient, and that women should be granted smicha so that they can accurately rule on questions of niddah.
I agree with R Alderstein that the time has come for women rabbis, and welcome his endorsement of that position.