The question then becomes, what is God's role in salvation, and what is the believers role if any? Is there in fact a synergistic aspect to salvation? The Calvinist would say no, Christ did not die for anyone he doesn't save, and the Arminian would say yes Christ died for the world. I want to use this passage as a jumping off point: Ephesians 1:3-6 NASB "Blessed be the God and Father of our Lord Jesus Christ, who has blessed us with every spiritual blessing in the heavenly places in Christ, (4) just as He chose us in Him before the foundation of the world, that we would be holy and blameless before Him. In love (5) He predestined us to adoption as sons through Jesus Christ to Himself, according to the kind intention of His will, (6) to the praise of the glory of His grace, which He freely bestowed on us in the Beloved." Let me state first, that while Paul later on in this chapter uses us and you as Jew and Gentile, in this verse the us is both Jew and Gentile. This is assured by the phrase, "he predestined us to adoption as sons through Jesus Christ to Himself." The ones that are adopted as sons and daughters are the ones that believe in Jesus whether Jew or Gentile.
So then, the above passage from Ephesians is an unalterable redemptive decree. What I mean is, it is stated in such a way, so if anyone was to change the meaning from reading another passage, it would simply no longer be true at all. Further, it states that God chose redemption before creation and it was so that His grace would be glorified. The glory of God's grace was his purpose in creating the world according to Paul in this passage. Think about that, God's purpose in creation was to glorify his grace. So then, what would glorify his grace the most? The fact that He would choose some for salvation and some for damnation? The fact that he would make a way so that some could choose salvation? Or, would the fact that he was in Christ, reconciling the WORLD/KOSMOS to Himself, not counting their trespasses against them. Of course, the greatest glory to His grace would be the latter. God's grace would bring the highest glory if he forgave everyone that he had created.
If you think that people who realize they have been redeemed praise his grace, how much more will some who did not think redemption was a possibility for them, praise his grace when they ultimately discover how amazing God's grace really is? Surely then, the words of scripture, Philippians 2:10-11 NASB (10) "so that at the name of Jesus EVERY KNEE WILL BOW, of those who are in heaven and on earth and under the earth, (11) and that every tongue will confess that Jesus Christ is Lord, to the glory of God the Father." However, there is real reason to proclaim the gospel as Paul proscribed in 2 Corinthians 5:20 NASB (20) "Therefore, we are ambassadors for Christ, as though God were making an appeal through us; we beg you on behalf of Christ, be reconciled to God." Isn't it a shame for someone to go through life, not realizing that they have in fact been reconciled to God? If someone gave you $10,000,000.00; had it in a bank in your name so that with your ID you could access it; but if you didn't know it was there, it would do you no good. God has redeemed the world through Christ. This is the pure pristine gospel. It is not proclaimed however. Evangelical and Orthodox doctrine has hid the truth.
Many who reject Christianity, do so because they cannot accept the schizophrenic message. At the absolute worst, let's say for the sake of argument that not all are saved. Let's say that some are saved, and some are given life here, and then are annihilated. Even that message would lead to the praise of God's glorious grace. Certainly, no one can honestly claim that Christianity as it is presently described, either by Arminians or Calvinists will lead to the praise of the glory of His grace. The truth is that neither group has the complete truth, and they both have partial truth. But, the pristine gospel that turned the world upside down is no longer being preached.