And Paul has the church judging the world and angels. What's your point?
The difference is that the twelve Apostles will be on twelve thrones judging the twelve tribes of Israel.
12 (and multiples of it) is an important number for Israel. It is a significant number throughout the Bible, and it always relates to Israel in some way.
Are you saying that a judge of Israel isn't allowed to share the gospel with a Gentile?
What's being said is that the gospel of the kingdom for the nation of Israel is not the same as the gospel of grace for the whole world.
What is preached to the Jew (prior to Paul, mind you) is different than what is preached to the Gentile (after Paul's conversion).
Cornelius was saved AFTER Paul's conversion. That makes him saved via the gospel of Grace, and was preached Jesus Christ as Lord of all (Acts 10:36), and how He was raised on the third day (Acts 10:40), and that, through His name, whoever believes in Him will receive remission of sins (Acts 10:43).
Romans 10:9-13, or an early version of it, perhaps.
What makes you think Paul didn't want John to go to the Gentiles,
What we KNOW is that Paul, and Peter, James, and John, agreed to go to different groups:
But on the contrary, when they saw that the gospel for the uncircumcised had been committed to me, as the gospel for the circumcised was to Peter(for He who worked effectively in Peter for the apostleship to the circumcised also worked effectively in me toward the Gentiles),and when James, Cephas, and John, who seemed to be pillars, perceived the grace that had been given to me, they gave me and Barnabas the right hand of fellowship,
that we should go to the Gentiles and they to the circumcised. - Galatians 2:7-9
http://www.biblegateway.com/passage/?search=Galatians2:7-9&version=NKJV
when Jesus had told John to go to them? The only reason for John NOT to go to the Gentiles, if he really had the words of eternal life from Jesus, is if his message wasn't really good news for them.
Rather, the reason for John not to go to the Gentiles is that his message wasn't FOR the Gentiles, but only for Israel. Remember, Christ said that He would return soon. Which meant that those who were saved under the gospel of the Kingdom needed to be ready for His return.
The Time of Jacob's Trouble is not good news for anyone but the nation of Israel. The Gospel of the Kingdom includes the Great Tribulation.
Paul and Peter preached the same gospel,
No, they didn't. At least, not at first they didn't.
even if the wording was a little different due to culture.
What difference in culture?
Paul was a Jew just as much as Peter was.
Unless you mean Jews vs Gentiles, in which case I would like to point out that the gospel that was revealed to Paul wasn't done all at once, and it would have taken even Paul some time to sort things out, especially because He was the first one to preach it.
I'm going to stop here, as RD seems to have addressed the rest sufficiently enough, though I caution you against appealing to tradition, which IS a logical fallacy.