#1. Seth Rollins

For the first two editions of the Superstar Shake-Up, the rumour was that AJ Styles and Seth Rollins would swap places. Many felt that there was a possibility of Rollins taking the Universal Championship to SmackDown as well.
Seth Rollins only really appeared on SmackDown during the Survivor Series rivalries, but apart from that, it's always been RAW for him. It would be a good change if he did briefly appear on SmackDown and picked up where he left off with AJ Styles.
Then again, that devalues the brand split a bit, but that's what the Wild Card rule has seemingly done. With names like Elias appearing as well on RAW, it seems like they've really loosened the rules of the brand split.
Either way, expect Seth Rollins to appear on SmackDown solely to ensure that even the very best superstars can appear on the opposite brand.
Becky Lynch has been challenged HERE.