My argument with replacement theology is that is ignores much prophecy and also ignores reality. Israel exists. For some, that is hard to accept. For me, I look on Google Earth and it's there.Usually, this debate arises when people compare Dispensationalism and Covenant Theology. I find I can't subscribe to either one fully. There's a healthy middle ground and, if I remember correctly, it's called Progressive Covenantalism. We, as Gentiles, do not replace Israel, but not all Jews are going to heaven either. Belief in Christ is the only prerequisite to entering Heaven, no questions asked. But there aren't two peoples. Since we are grafted in, we are all one branch. So in the end, there are only parts of those two branches of theology that get it right, in my opinion.
It is clear to me that God's plans include literal Israel. Those who argue have to relegate everything to the realm of symbolism. For example, during the great tribulation, 12,000 young men from 12 tribes will preach the gospel to the world. I don't accept that as symbolism.
It is also clear that there is no separate salvation for Jews. That heresy is promoted by John Hagee and some others. I don't know how they get that idea any more than I can understand the replacement people. Sure, when Israel was not a nation, it was understandable. Even then some believers saw it coming, as far back as the 17th century.