I have seen "Dead Poet's Society" dozens of times, so rather than tell you my feelings about it I think I will pose a number of questions. Feel free to pick up on any one of them -- or more than one. Or, if you are moved, ask and answer your own questions. I will number the questions for your convenience.
1) Nwanda -- punk or hero?
2) Is the suicide glorified in any way? Or do we as readers see that Neil has options and therefore the suicide is seen as rash and misguided?
3) Is the movie, taken as a whole, more celebration or indictment of the carpe diem philosophy espoused by Keating, Whitman, Thoreau, etc.? In the end you have a suicide, a firing, and an expulsion; but you also have self-empowerment (Todd), love (Knox), and a whole bunch of teenagers who are thinking more independently than they were before.
4) Even if we can agree that Keating isn't responsible for Neil's death, does he do anything wrong? Is he blameless?
5) Fun symbolism Department. Birds. At the beginning there is a montage scene of huge flocks of birds rising and turning all together (they're wrens, in case you were wondering). Then there is an immediate cut to the kids going down the circular stairway all together (first day of school), the same directional flow as the birds in the previous shot, bringing out the "flock mentality" of the kids. Later, Knox rides his bike through a huge flock of Canada geese on his way to see Kris jump into the arms of Chet. Upsetting the flock! Also, two scenes of kids walking in the courtyard provide bookend symbols in the movie. First you have Keating encouraging his students to walk to the pace of their own drummer (a Thoreau line!) with the Latin teacher watching from the teacher's lounge above; then, at the end, you have the Latin teacher with his students in the courtyard, walking in unison, reciting something they have memorized, following already made footprints in the snow, with Keating watching from the teacher's lounge above (they wave to one another). If the style of walking is an indication, it's back to normal now in the school.
More later, but this should get you started.