In all situation: X5R has too short flight times and too big Raw-files for video. X5r is a very good solution for photographers, but the Tornado with the GH4 has RAW photo too and you have no stress to get your picture with right focus (seems to be a serious problem with the X5), exposure, etc. Even it will be possible to mount a A7r2 on the gimbal with the highest resolution possible at the moment.
GH4 can't do RAW video I don't believe.