I love Lord of the Rings. I believe that, as a Christian, the author probably couldn't help but include many parallels with the Bible, but I have never thought of it as being meant to convey the gospel. i would never use it to explain anything to unbelievers, but it is an enjoyable set of films in which good triumphs over evil, and where the crown is eventually restored to it's rightful heir. I doubt that any of the characters is supposed to represent Jesus, but, as I said, it can be hard for a Christian writer not to include aspects of scripture in both their character profiles and the general story-line. I like this, as it gives each person the opportunity to read into it what they want to. i know I certainly watch it from a scriptural perspective, and rejoice in what the story brings to memory from the Word.
Each person should rely on how the holy spirit reacts inside them. But thewy should also never judge anyone else for feeling differently about it. Paul said that what one person has the faith to do, another does not, but that neither should judge the other. He also said anything that does not come from faith is sin, so if someone watches it, feeling that it is wrong, then they are sinning. And if anyone causes a brother to sin, by watching it in front of someone without the faith to do so, or if by watching it they upset a brother, then they sin.
So it's not so much a spiritual debate as it is a personal choice, with the guidance of the Holy Spirit, with love for your brother in Christ.