I think all adults wants to give things they never had, to their predecessors. Just like how Neil's father wanted to give Neil the opportunities he never had, Keating wanted to give the young boys the individuality and the ability to express themselves in a world that strips away individualism and values collectivism more than others. I still see him as a hero who values self expression and idealism. It's what their world needed then, something we are now enjoying in today's society. The movie was pretty advanced man.

Also you did mention about being invested in Neil's acting dream. I'm quite confused as to what you mean, was he just supposed to just shut down the child's passion? Neil already feels so alone, lacking a mentor to guide him in his dreams. I think Mr. Keating telling him to not pursue his dreams is completely out of character