Actually the immigration acts of the 1920's had special consideration for "Hebrews" in a negative way. Even with the Holocaust antisemitism in the USA was very open until the early 1960's. This including very open quotas for Jews in Ivy league schools and many other universities, quotas in professional schools (medical, dental, law), "restricted" communities and subdivisions where Jews (as well as blacks and Hispanics of course) were prohibited from owning property, and certain companies were well known for their unwillingness to hire Jews or if they did, opportunities for advancement were quite limited. This is, of course, on top of the usual social antisemitism of club membership, hotels, personal slurs from individuals both public and private and so on.
While the Balfour Declaration had stated the approval of HMG for a "Jewish National Home" in Palestine, after WWI through 1948 OTL the British did everything they could to prevent or minimize Jewish immigration to Palestine. Absent the Holocaust I see no reason the British would be any more accommodating than they were OTL with the Holocaust. You still might get Israel, and with a larger Jewish population in Europe a larger Jewish population but then again perhaps not.
Even absent extermination, the question is how bad would Jews be treated in Nazi occupied Europe, and other European countries (Italy, Hungary, Romania, etc). I expect the situation of the Jews of Europe in 1945 would be substantially worse than before the war - confiscation of assets/property (which likely would not be returned) and the sort of discriminatory laws that got worse during the 30s and the war still intact.
While eliminating the Holocaust is a wonderful thing, this will not make life rosy for those who survive the war. IMHO the antisemitism in American (and western Europe) will continue longer than OTL.