1. Yes, my opinion about Mitch did change as the book went on. As a young man in college, Mitch found a friend away from home. This friend happened to be Morrie, his professor. However, after Mitch graduated he was confronted by a world full of a "false" culture, foreign to a healthy one you can personally create. Mitch's dreams of becoming a musician quickly drifted away, and became hidden behind the pursuit of money and a powerful career. As a sports columnist, Mitch was flipping through the television, looking for topics. Coincidently, he ran into a show broadcasting Morrie and his heroic fight against death with a forgiving outlook on life. Mitch, plagued by his promise of staying in touch after college, was disturbed even more at how time and sickness had changed the old man. He visited the old professor, and after having his last fourteen "classes" with Morrie on consecutive Tuesdays, Morrie finally passed away.
Previous to Morrie death, it finally came clear of Mitch's change when Mitch must accept that Morrie is dying and will not be with him on earth for much longer. Mitch's urge to yank the oxygen tube from Morrie's nose is an action of fear; he is afraid of what will become of him without Morrie to guide him (a repeat of what happened after college).
2. I think that it is not fair to say who got more out of their Tuesday meetings. The reason for this is because although Mitch needed the guidance and lessons, Morrie also needed Mitch to know that Mitch fulfilled his promise of coming back to see him.
3. I do not think Mitch would have come back to Morrie's house the second time if he hadn't been semi-idled by the newspaper strike. I say this...