Considering just speeds up the process of jumping from group to group, which Blizzard already allows due to the group finder, I can't imagine it would be bannable.
It does nothing you can't already do without the addon. With that being said, they just changed how server hopping works so it's not as effective as it used to be (prior to prepatch)
I, and everyone else, have used Server Hop and/or other realm hopping addons for almost the entirety of WOD and never experienced any issues.