MTV has to become something different than it has been or it won't survive.
MTV knows this. And the Shannara series is just one of many steps they are taking.
MTV has made a living providing content to the children of those who have money to pay the cable bill. To date, they have not cared one little bit about the bill payer's opinion of their content (most of them hate it).
With the rise of cable cutting and direct-to-consumer models for cable channels, MTV has to start providing content people with money will buy.
Because the parents of kids aren't going to pay a penny so their kids can watch "My Super Sweet 16" or whatever other garbage they have running now.