#3 Thrash Brock Lesnar

Even in their nuanced dynamics, if there is a common enemy to the Shield, it is Brock Lesnar. Except for the main event of Wrestlemania 31 and Summerslam 2017, none of the matches involving a member of Shield and Brock Lesnar were particularly impressive, and most of the times, the Beast Incarnate went over the younger talents.
Thus, building into the Wrestlemania 35 Universal title match between Brock Lesnar and Seth Rollins, WWE could have a segment where all three members of the Shield return and lay waste to the reigning Universal Champion if he bothers to show up.
Cody has no chance against John Cena? Details HERE
Such an angle would propel both Rollins' and Ambrose's popularity to a whole new level. Moreover, this beating would help the fans get over the underwhelming reunions the Shield had in the last two years.
In short, such a segment will leave a sweet memory in the minds of every Shield fan forever.