I think this is only half the story, only because he only got to live half a life.
If he were still alive today, I think he would still be a Zionist, in that he advocates that the state of Israel exist. However, he would be on the hard left of the Israeli political spectrum (think: Arie Peliger), and would call for the Israel government to quick picking on the Pallies and quit imposing an “apartheid” or “segregationist” or “Jim Crow” style system upon them.
Interestingly, the Six-Day War of Israeli territorial aggrandizement took place before his assassination, so he had to have heard about it and formed an opinion about it. However, history doesn’t give us any credible read on what he really thought of it. Maybe MLK was too focused on domestic issues to give it much if any thought. I think that if he would have lived, the events of the Six-Day War would have slowly made him less friendly toward Israel, and definitely hostile to Israeli political figures like Golda Meir and eventually Benjamin Netanyahu.