I get the point the author is trying to make: that you can distill argument down to its essence, and that you should.
What the argument fails to take into account (to name two) is:
1. We have “splits of authority.” One court says the law is Y and one court says the law is X. Now it’s roses are red in this jurisdiction and pink in another. The whole thing goes off the rails.
Argue your point as best you can and hope!
2. Many statutory schemes have become insanely complex so as to make distilling arguments to their essence nearly impossible. Additionally, each piece of complexity is another opportunity for courts to diverge in interpretation (see point 1).
To be sure, the classic common law claims —- murder, robbery, larceny, battery, etc — are amenable to this type of distillation, but that’s so little of what the practice of law is anymore.
Students get an education like described in the article, and then they come out woefully unprepared for the real world.