The thing is that he is consistent in what he is proposing - whether he speaks to Israel (or American Jews) and to Palestinians (or the Arab League).
I was watching what came into twitter for "john Kerry" - there were people allied with the Palestinians angered that he made the case to Israel based on the demographic time bomb rather than the fact that the occupation is wrong. What they miss is that he will not persuade many in his audience to follow him if he argued - as they do - that the current occupation makes Israel an appartheid state.
The problem is that each side needs to see the same solution as better for them than the alternative path they are on. This is why JK risked angering Israel when he spoke frankly on Israeli TV when he spoke of the consequences to Israel of NOT agreeing to a 2 state solution. (The same things he told an American Jewish audience earlier). Many on the right in Israel referred to it as "threatening" rather than observing logical consequences. That many in Israel are more easily moved by knowing that their country can not be what they want it to be unless they end the occupation may not be the reason Palestinians want to hear, but it gets to same point.
I thought his case on Iran was the strongest part of the speech. It is a very compelling case. As he is going to the House this week to answer questions, it was great to hear his concise, but detailed explanation of what the interim agreement is. (It reminded me of his responses on the Start treaty - dealing with very detailed, esoteric issues, but always clear and reasoned. ) I hope this bodes well for the hearings.
I loved that he ended with a few lines of the Haskiveinu - which was a very nice way of ending a speech on peace, but where in many parts he was confronting some opposition. The rabbi at the synagogue that we went to in NJ always spoke to the kids of picturing the whole world being under a big "sukkah" or tent of peace before that prayer was said. Here is a you tube I found of the song being song as a round - as a lullaby - where the tune is one commonly used.