The intensive US negotiations on the Iran happened in 2014 and 2015 -- it was very early in 2014 (I think March) when both Israel and the Palestinians made it clear there would be no successful negotiations. To imply that Kerry chose to work on Iran rather than continue and make this happen is ridiculous. One summary that I believe essentially said that Kerry wanted peace more than either side did. The fact is he returned to Israel in summer 2013 when they were willing to meet at great personal sacrifice, when Teresa was ill.
The peace talks blew up and within months there was the terrible war in Gaza. What the Times of Israel leaves out of their story is that Netanyahu stabbed Kerry (and Obama) in the back. Kerry came to help get a ceasefire that Netanyahu PUBLICLY wanted, but privately didn't. When an attempt to get a ceasefire began in Paris, Hamas sent their proposal via Oman. As happens in all these ceasefire negotiations where neither Israel or the US will speak to Hamas - Oman gave the proposal to Kerry and various European foreign ministers. As he was asked and as was the norm, Kerry sent it to Netanyahu and awaited the Israeli counter proposal. Instead, Netanyahu dramatically called the Knesset together and introduced it as the American proposal and it was angilly defeated.
As would have it, I was in Europe at that time with a Jewish British friend. Her comment - which should be asked of the Times of Israel was why did Israel think it was the American responsibility and their fault when obviously Israel and Hamas were the parties unable to find peace.
Here, this oped is ridiculous - in that it does not ask why Netanyahu has thrown road blocks in the way and has been utterly dishonest.
As to the question, "what are you hoping to accomplish?" My guess is that it is the Hail Mary pass of all Hail Mary passes hoping to wake up Israel and get them to at least freeze things so that maybe they could under better future circumstances find a way back. A second possibility - he had to defend himself and Obama from Netanyahu's disgraceful full blown raging temper tantrum against them. Adding what could have been was in a very real way an answer to why the US waited 12 years. It didn't. Condi Rice tried in the second Bush term, George Mitchell and Dennis Ross tried in Obama's first term and Kerry did everything he humanly could have in the second term. The failure was that of both the Palestinians and the Israelis. A mediator could lead them to water, but could not make them drink.