One good thing about the 500,000 Russian gentiles (ie those who have no Jewish yichus on either side, at all) in Israel: at least they hate Arabs and Muslims with a passion!
Imagine if Israel was flooded with 500,000 genuinely Jewish American liberal and left wing Jews?! They jus' love Arabs and Muslims, also with a passion!
A subversive Alan Dershowitz, a Sarah Silverman, a Barbrara Streisand, a George Soros, a Michael Lerner, a Phillip Roth, a Dianne Feinstein, a Richard Dreyfuss etc etc all coming on Aliya/fleeing the USA, let alone 200,000 anti-Israeli American Kiryas Yoel/Williamsburg Satmar hassidim, doesn't even bear thinking about!
They may not necessarily be allowed in by the Israeli authorities!
The Messianic Kibbutz Galuyot ("Ingathering of the Exiles") will be quite selective when it comes. Not every Jew will be allowed in to Eretz Yisrael: "Today, whoever wants to can ascend to Jerusalem. In the future it will be by invitation only!!" (Talmud Bava Basra 75)