Any republican that goes on the MTP must be a complete sadist. I can understand why they would go when it was run by Tim Russert prior to the rise of Fox News. But in this day and age, MTP is as useless as an advanced degree from OU.
I don't think MTP was ever that influential on its own. The people who actually watched those shows regularly were political junkies whose minds were already made up. Its real influence came from guests being quoted in news and commentary articles and clips being shown on the news. However, nowadays I don't think many people get their news from those sources anymore. They've all thrown away their credibility, so there truly is no point in any Republican going on those shows. You're going to get some unprofessional hack out to make you look bad and help pitch your opposition's talking points.