Truth comes from the Bible, and it's not complicated. Things that are unclear in the Bible are just unclear. An example would be: The Bible doesn't mention who wrote Hebrews. Being part of the Bible, Hebrews is important, but exactly who wrote it isn't.
Truth does not come from a mysterious board of directors. That board has had to do a fair amount of back peddling over the years.
As for the prophet angle, the witnesses believe that they have a heavenly ruling class (the remnant of the 144,000) that will go to heaven. In the late 1800's, the founder, C. T. Russel and his Bible students were believed to be of this class. Sometime around 1920 the Witnesses increased to over 144k. It was announced that there was also an earthly class that would live forever on a perfected earth. At the time of this revelation it was decided that the anointed group would have to have been aware of their heavenly calling and baptized by 1914. In other words, the anointed were to be old enough to make their own decisions in 1914.
Matthew 24:34. "Truly I say to you that this generation will by no means pass away until all these things occur." By reading the preceding verses it is obvious that Jesus was referring to the end - after the great tribulation.
The witnesses believe their anointed are that generation. The anointed were dwindling or had passed, and the end hadn't yet come, so it was decided there are now new replacements to take the place of those that didn't make the grade.
The witnesses are sincere true believers, but don't consider non members to be Christians. Their hearts are in the right place. When they come to your door, they truly want to help. They don't want or need your money. Tithing was part of The Law given through Moses that Jesus fulfilled upon his propitiatory sacrifice.
I learned a lot from a one on one weekly Bible study with a witness that went on for a few years. It ended when I moved out of state. My teacher made a Christian out of me. I gained a solid understanding of the Bible, and faith beyond what I would have believed possible.
After the move, I found myself wanting to study the whole bible, without a slant. If Bible scholars can't agree on the meanings of small parts of It, I don't need to take a side on them, or make something more out of them. The over all message still comes through.