disagree! I, and many others, have a rotating list of top 5 choices of schools. Also, we would need to compare financial aid packages from different schools, so holding two acceptances at a time severely limits options, especially when you need time to discuss with spouses, parents, friends on cost vs. happiness.
And for the second point, I disagree as well. If everyone heard back in March, it'd make the process all the more stressful. What if in March you find out all your schools waitlisted/rejected you and you had to reapply? You'd have 3 months to scramble with better activities, higher scores, etc. (when you had assumed you'd get in) Plus, tons of people would have to interview at every last school instead of withdrawing their interviews for people who have 0-2 interviews.
on the original question, I'd want to say:
1. no waitlisting everyone who isn't accepted after the interview. If I'm at the bottom of the list, I want to know now. There is no need to maintain a 500 person waitlist when you know in past years you've taken 10.
2a. No Gray's Anatomy-length secondary essays. I'm looking at you, Duke and UCSD.
2b. On the other hand, do have secondary essays with "Why X School?" I was able to stop myself from applying to some schools because of this reason alone--I could not find substance to write 100 words.
2c. Disliked the schools that had no secondaries, or such easy secondaries (check here if you've committed a crime, check here if you've done time) because it didn't effectively screen me out of paying $$. I'm selfish.
3. Don't make secondaries should cost over $100 each.
4. Stop biasing against CA residents.
5. Rejection letters should be nice. I hated all of the 3 liners after handing in $80 that said "We got 10000 applicants for 100 spots, so it was competitive. Sorry we are unable to offer you a spot. Thanks and good luck." I thought Harvard's was very nicely written.