I believe we need to know what happens in Epi 2 and 3 before I would say Obi Wan is a tragic figure. There is an arrogance and insensivity I see in him in Epi 1 that seem to be his character flaw. I refer to his "pathetic lifeforms" comment on Tattoine. Anakin has salvaged the situation and Obi-wan is resentful of Qui-gon liberating Anakin from slavery. I would also say Obi-wan was one of two Jedi to survive Vader's purge. Yes, to live in obscurity *knowing* (whatever it is that he will know) is a tragic burdeon. I see the smile before Vader kills Obi-wan is the revelation that whatever he has experienced was wothwhile. That is the glimpse that bridges the past (prequils) with the future. And I wonder whether Vader (or the Emporer) knows that Alderon is key to the survivle of hope. That both Luke and Leia had ties to Aleron that Vader targeted for destruction in Epi. 4 but both escaped.