Yes, I do believe that he should be credited with laying the foundation for the development of the Pentecostal view of Spirit baptism. While he may not have embraced the entire, current Pentecostal view of Spirit baptism, he did emphasize the need for personal encounter with God, which is an essential pillar of the Pentecostal experience. His emphasis on the full surrender of the heart and the subsequent work of the Holy Spirit in the lives of believers opened the doorway for us to seek a deeper experience with the Spirit. I don't think that it would be fair to discredit Wesley's influence on Pentecostalism just because of a single point of contention.
My viewpoint seems to most closely align with Wesley. I disagree with Fletcher's views on entire sanctification, as well as much of the subsequent Holiness movement's views. As much as I would like to believe that we as Christians can be free from all sin, intentional or unintentional, I simply do not find evidence for this in the Bible. We are all fundamentally flawed creatures, and though we may turn away from conscious sin and become more holy through the work of the Spirit, it will always be a battle. If we say we have no sin, we deceive ourselves, and the truth is not in us – 1 John 1:8.