Regarding Finn Balor's WWE pay-per-view debut, it was always scheduled to happen at SummerSlam but original plans had him facing Chris Jericho as Roman Reigns vs. Seth Rollins was the planned title main event. Original plans also had RAW getting the main WWE Title and SmackDown getting what is now the Universal Title, won by AJ Styles.
Reigns' WWE Wellness Policy violation changed those creative plans and WWE made the decision to put another babyface in the top RAW slot, pushing Reigns down the card as punishment.
Source: Wrestling Observer Newsletter
Subscribe to The Wrestling Observer by clicking here. Each issue has coverage and analysis of all the major news, plus history pieces. New subscribers can also receive free classic issues.