No Reformed, amillennial or postmillennial Christian that I know of believes that they're replacing the Jews in God's eschatology. In fact, it's the modern dispensationalist who thinks that the Jews have been replaced by the church until the church disappears in the rapture!
According to English and every other dispensationalist, the Church has replaced Israel until the rapture. The unfulfilled promises made to Israel are not fulfilled until after the Church is taken off the earth. Thomas Ice, one of dispensationalism’s rising stars, admits that the Church replaces Israel this side of the rapture: “We dispensationalists believe that the church has superseded Israel during the current church age, but God has a future time in which He will restore national Israel ‘as the institution for the administration of divine blessings to the world.’”
-- From the thread Answering the "Replacement Theology" Critics (Part 1)“...the very category of ‘replacement’ is foreign to Reformed theology because it assumes a dispensational, Israeleo-centric way of thinking. It assumes that the temporary, national people was, in fact, intended to be the permanent arrangement.”
-- From the thread Replacing “Replacement” Theology"The historical premillennialist's view interprets some prophecy in Scripture as having literal fulfillment while others demand a semi-symbolic fulfillment. As a case in point, the seal judgments (Revelation 6) are viewed as having fulfillment in the forces in history (rather than in future powers) by which God works out his redemptive and judicial purposes leading up to the end. Rather than the belief of an imminent return of Christ, it is held that a number of historical events (e.g., the rise of the Beast and the False Prophet) must take place before Christ's Second Coming. This Second Coming will be accompanied by the resurrection and rapture of the saints (1 Thessalonians 4:15-18); this will inaugurate the millennial reign of Christ. The Jewish nation, while being perfectly able to join the church in the belief of a true faith in Christ, has no distinct redemptive plan as they would in the dispensational perspective. The duration of the millennial kingdom (Revelation 20:1-6) is unsure: literal or metaphorical."
-- From the thread Four Views on the Millennium
To believe [the world will wax worse and worse and lawlessness will increase until the Great Tribulation], you must conclude that either A) Transformed lives don't accomplish jack squat when working in groups, meaning groups can't be transformed B) God doesn't plan on transforming lives in the future, or b) The "transformed life" is but a temporary phenomena.
-- Alex Murphy, November 9, 2007
And Jesus answering saith unto them, "Have faith in God. For verily I say unto you, That whosoever shall say unto this mountain, Be thou removed, and be thou cast into the sea; and shall not doubt in his heart, but shall believe that those things which he saith shall come to pass; he shall watch the mountain groweth before him until it fills the whole earth, even unto crushing all the saints beneath it, yet yeah verily ye will declareth victory over whatsoever ye saith until death.Catholic Cleric: Jesus Cancelled Biblical ‘Chosen People’Therefore I say unto you, What things soever ye desire, when ye pray, believe that ye receive them, and keep ye deluding yourselves until that day when I will return unto you and finally accomplish Myself what ye could not do in My Name.
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-- Mark 11:22-24, Pretrib Dispensational Version
Thank You Alex Murphy for the opposing view.