#3 To add star power to the match after losing Rollins
Team Hogan vs. Team Flair was a big deal when the match was first announced. And this is because Seth Rollins was announced as the Team Captain for Hogan's team, which made it a star-studded affair.
Of course, as time passed and the Hell in a Cell debacle happened, a rematch would be booked for Saudi Arabia and Seth Rollins had to bow out of the team. Roman Reigns would be announced as the Team Captain for Team Hogan, and the match lost a significant amount of star power with the Universal Champion's departure from the said contest.
McIntyre may not be the same level of star that Rollins is, but he belongs in the upper mid-card. Adding someone like say, Buddy Murphy, while building a new star, would have just made the match much less must-see.
McIntyre's presence was certainly needed!