I found this critique of Anti-Supercessionism helpful. Here are some good points:
"But Soulen is arguing that blood descent from Abraham was the backbone of the covenantal arrangements with Israel, and this point is simply false. Right from the beginning, the covenant embraced many who were not in anyway related to Abraham by blood. All the male members of Abraham's household were circumcised (Genesis 17:12-14), and in a household that included 318 men of fighting age (Genesis 14:14), this must have been a sizable number of men - far more than the blood descendants of Abraham, which at the time included only Ishmael!"
"When Israel came from Egypt, they came out as a 'mixed multitude' (Exodus 12:38), including thousands of Egyptians who did not want to hang around Egypt after it had been nearly destroyed by plagues. It was never the case that 'the family identity of the Jewish people as the descendants of Abraham, Isaac, and Jacob' was the foundation of the faith of Israel."
"Within the covenant, those who are not blood descendants of Abraham have always outnumbered those who are."
I think this hits at the fundamental error in Dispensationalism, mistaking the Abrahamic Covenant as an ethnic covenant, rather than a spiritual covenant.
Someone recently asked me what I thought of Supercessionism as a label. There certainly are and have been Supercessionists within the church. That is, there are Christians who believe that the church replaces Israel.
However, "Supercessionism" or "Replacement Theology" is often applied to anyone who is not a Dispensationalist. There are other options besides Dispensationalism and Supercessionism.
Just to clarify my view, the church doesn't replace Israel. The church is Israel. They are different labels for the same group of people.
I'm sure that Mike Vlach will still label me a Supercessionist of sorts (perhaps a Practical Supercessionist?). Whatever.