3 reasons why there could be a Shield reunion very soon 

#1 Because it might be for the last time

Dean Ambrose will leave the company after the expiration of his contract

It has become a well-known fact that Dean Ambrose will leave WWE after the expiration of his contract with WWE, this April. Thus, who would not like to see the reunion of one of the most dominant forces in the history of WWE for one last time.

With Roman Reigns expected to return very soon, creative could have the trio reunite for the very last time. Also, with Ambrose saying goodbye to WWE in April, this reunion could be short lived. Thus, WWE could have The Shield reunite to take down a heel Lesnar before WrestleMania 35 (that powerbomb through the announcer's table).

Also, WWE could go on to have them align once again and do their trademark fist bump for one last time, if and when Seth Rollins wins the title at WrestleMania 35.

Imagine that, how is that for a WrestleMania moment? The Shield doing a fist bump with fireworks going off in the background to end WrestleMania 35, now that's what is 'best for business'.