[I have been wary of getting involved in the latest polemic, this one surrounding the decision by SAR and Ramaz to allow women to wear Tefillin to the school minyan. However, after following the various postings and threads on Facebook and elsewhere, I decided to briefly (with an appropriate amount of adrenaline) summarize my thoughts on salient aspects of the issue. As you can see, I view the specific question as almost secondary to broader issues.]
This issue has generated
 so much anger, so much frustration been fed by so much prejudice and 
ignorance that I don't know if a reasoned discussion is possible. Still,
 a few points to consider:
1) For those who buy into thoroughgoing,
 radical egalitarianism and reject Judaism's gender distinctions there 
is nothing to discuss. They will aggressively defend any move in that 
direction and will vilify anyone who disagrees. Orthodoxy will, I 
suspect, find that with those of such opinion there is only a dialogue 
of the deaf.
2) There has been much discussion of the description of women who don Tefillin in public as being guilty of מחזי כיוהרא. This phrase does does not mean 'appearance of 
arrogance,' but of being presumptuous (just as מחזי כמבשל doesn't mean 
cooking, but appearing to cook which will lead to people suspecting 
one's actions or possibly leading one to cook). Demonstratively practicing
 a mitzva that one is not obliged to do, according to Tradition, impugns
 others who do not do so. That, for example, is why R. Israel of Brunn 
(Resp. Israel Bruna no. 96) forbade wearing one's tzitzit outside of one's clothes. The category has
 ABSOLUTELY NOTHING TO DO with the questioning the motives of the 
individual. It does question the sensitivities of the individual who is 
ipso facto making a statement about others who do not accept their new 
practice. Did
 anyone ask other women if they are put off by women putting on Tefillin, with
 the implied judgement that they are less spiritual or less committed?.
3) For the same reason, there is more reason and room to 
allow women to wear Tefillin in private, not because it is wrong 
(necessarily), but because doing so keeps their act of piety pure. That 
is true of every Humra, and rabbis should condemn people who use any personal Humra for self-aggrandizement.
4) I am stunned by the persistent, superficial equation of Black Hats and Tefillin. Yes, black hats are 
frequently arrogant displays (and prove my point about מחזי כיוהרא).  However, wearing a
 hat has no religious significance, though it is socially significant as
 a sub-group marker of identity. Adding religious obligations (whatever 
the legal mechanism in force there, נדר or חובה) is a deadly serious 
question. Those who dismiss it in the name of spiritual self-fulfillment
 only show that they are insensitive to the long term issue of sins of 
omission, when these same women may not be able to maintain their newly found personal obligation. And the reply that there are men who aren't fastidious in their observance is myopic. Since when do we justify religious lassitude by pointing out that of others?
5) I have spent thirty years fighting for the right of 
learned rabbis to have their own halakhic opinion, contrary to some Rashe Yeshiva who deny 
them that prerogative. After seeing the half-baked, uninformed and 
revoltingly disrespectful way in which Facebookers and other Commenters treat 
Hazal, the GRA, the Rema, the Arukh HaShulhan etc. I begin to wonder. 
Orthodoxy maintains a balance between deep reverence for Tradition and 
Gedole Torah, alongside the need to confront new questions and 
challenges. R. Shlomo Zalman Auerbach zt'l used to predicate his hardest
 decisions on the agreement of colleagues. He was a giant of Torah and Piety and Humanity who was attached to the entire Jewish People, from Haredi to Hiloni. Still, he was cautious and responsible when he ventured into new territory. Yet here are people filling the Blogosphere, the Newspapers and Social Media who blithely toss 
out established halakhic categories as if they were so much detritus because 'it 
makes no sense to me.' As my revered teacher, Rav Soloveitchik זצ"ל once 
said, innovations are the lifeblood of the Torah, but they occur within its autonomous sphere. You 
engage the system. You don't violate it by judging it because it doesn't
 fit superficial, media driven ideologies.
6) At the same time, there is no room in principled Halakhic discourse 
for base vilification of either side. Hence, the insidious attacks on 
Rabbis Harcstark and Lookstein are equally contemnable. 
7) I have no idea if 
Rashi's daughters wore Tefillin. I actually doubt it, because Tefillin 
was a largely neglected mitzva in medieval France, and Rashi actually 
was against women reciting blessings over mitzvot that they weren't 
obliged to fulfill. If they did, I am sure they did not where them in 
Shul. 
8) Rashi's daughters were, on the other hand, learned. This 
brings me to another example of herd-like thinking on this issue. There 
is no such thing as 'The Forbidden City' of mitzvot from which women are
 barred and that must be conquered. Each mitzvah, each obligation, has 
its own parameters and dynamic. Talmud Torah for women is easily 
allowed. Mitzvot from which women were exempted and for which there are 
larger reasons to continue that exemption, are another story. It's not 
all of one piece, unless you are determined to impose an egalitarian, 
leveling agenda on the Torah. Such a position is, frequently, no longer 
Orthodox because it denies the integrity of Halakhah and lacks the 
intellectual and spiritual modesty and humility that are its essential 
ingredients.