My first comment is that to preach for 25 minutes at any CofE ceremony is considered bad manners; to preach for 25 minutes on a socially and theologically contentious issue at a wedding with guests of varied beliefs, is plain rude. The rudeness will be what people remember about you.
My second thought is, of course, that no person should ever swear to unconditionally 'obey' another, under any circumstances.
On the one hand I think it's a very bad basis for a relationship, deeply bad for the man as much as the woman, bad to the extent I think people who actually carried through such a commitment would do themselves psychological damage. Like an S&M contract, however, I suspect this Christian wording is more of a pose than a real commitment to destroy one's own moral agency.
I think Christians should consider the main contentious points between man and wife. The wife is not ready to have sex yet after child birth. The wife does not want to work full time, because she wants to spend more time with the children. The wife does not want to abort a pregnancy although money is tight. The wife does not want to welcome a third party into the marital bed. These are conflicts which have broken up various friends' marriages. I've also known couples fight about whether the wife should breastfeed. and I think obedience by the wife in any of these cases would have been wrong.
(ETA - not that abortion or three-way sex is bad, of course, but that it shouldn't be done out of obedience by someone who doesn't want it.)
But going further I think that agreeing to obey any order is equivalent to agreeing to commit any atrocity. Thus nobody: not a child, not a soldier, and certainly not a wife, should ever make that commitment.