Is the biblical separation of Israel and the Church an “unfortunate consequence of Dispensationalism,” as some critics say?

Not if it is biblical truth. Was it an “an unfortunate consequence” of the Law that the Jews were separated from the Gentiles, or that the Levites and Priests were separated from the rest of Israel? Separation to the work God has given you is never a “consequence.” Is it possible to feel hurt or upset because you are who you are? Surely. There are men who wish they were women, women who want to be men, Israelites who want to be Priests, Gentiles who want to be Jews, people alive today who wish they lived a thousand years ago, and the list goes on and on. This is not new, and the Bible advises us that “each one should retain the place in life that the Lord assigned to him and to which God has called him” (1 Cor. 7:17). The point is this: God makes us who we are and calls us to different functions for Him. God delegated to His son the power and authority to create “one new man” out of both Jews and Gentiles, and the creative work of God is never an “unfortunate consequence” of anything.