It's a question of whether or not you think that's a good thing or bad thing. Quite honestly, I think the evidence speaks for itself. Which apostle traveled the furthest and reached the most people? By your fruits shall ye know them.
It was Paul's decision to primarily focus on preaching to the Gentiles that matters most, as that led to the explosion of Christianity in the coming centuries. And looking at his writings, it's clear that his biggest contribution was explaining to the Gentile Christians that converting to Judaism first and obeying the Mosaic Laws...circumcision, yearly sacrifice, etc...were not necessary for salvation. It comes through faith in Christ, not works, and the Law had been fulfilled by Jesus, so we're no longer bound by it. Personally, I think that perfectly fits the context of Jesus' ministry on Earth: His lambasting of the Pharisees for the fake piousness, His insistence that He was the way, truth, and life, etc. So I think Paul has made the most profound contribution to Christianity outside of Christ Himself. And that is a wonderful thing.
I am not arguing against Paul’s influence but he has always obtained great theological debate about his works because first he was not like Peter, Matthew, Mark and John an apostle of Yeshua before the ressurection, nor ever among any of them until after his experience “on the road to Damascus”, and then not until about fourteen years after that, and yet his body of works dwarfs the others in volume.
It dwarfs the other in volume and in reach of theological matter so much that it is not entirely impossible to imagine a Christianity not so very different from today for the most part, if we never had the gospels of Mark, Matthew and John. Of course it enters theological debate that the one apostle who knew him not when he was on earth, provides the bulk of theological belief about what is a Christian.
Of course there are religious studies by academic biblical scholars that have suggested the differences between Paul and the Church in Jerusalem, led by Yeshua’s brother James, were greater and somewhat different than as reported by Paul and Luke. But we can learn too little precision of them as it seems the bulk of the Church in Jersusalem fled Jersusalem in the rebelllions against Rome - that nearly destroyed the city, and what works of their own that they had have been lost with them.