Hamlet.  In those plays, people are themselves destroyed by their flaws.  By contrast, in Othello, the title character destroys himself by first destroying someone else.  It is much sadder, to see Othello do this than it is, for example, to see Hamlet eating himself away from the inside.  It is more painful to watch Othello and Desdemona's love destroyed.

I think that there is a case that can be made in support of the statement.  That being said, I think that it is near impossible to quantify which Shakespearean work is more painful than another.  One is left fairly hollow after reading all of them.  I do think that I would separate myself from the “exciting” element.  There is little I find exciting in the drama.  Perhaps, a case can be made for Iago’s machinations as being exciting, but I am not entirely certain that “exciting” is the best description for what is happening in the tragedy.  The pain that is evident in Othello’s doubt and insecurity, as well as Desdemona’s loyalty that really goes unrewarded and the entire notion of Iago, the personification of malevolence, ends up winning.  These examples of pain are terrible to witness and represent human beings at their most pathetic.  Yet, I think there might be more “excitement” in a Macbeth or even with a Romeo and Juliet, where there is anticipation and a clear sense of tension being developed with an apex of action.  I think that what is being developed on Othello is more along the lines of a devolving of a man who truly accomplished a great deal both on the battlefield and off of it.  However, his own demons and personal insecurities end up being the catalyst for his own degradation and assisted by treachery, anyone cursed to love him gets brought down with him.  I don’t see the “excitement” evident here, but I do think that the rest of the quote has validity.