#1 No viable opponents for The Shield
The New Day is on SmackDown Live. The Wyatt Family is nowhere to be seen. The heel alliance of Lashley, Corbin, and McIntyre is hardly a threat. The Shield could always come back but whom will they feud with?
I mean let's list out all of the potential trios on RAW at this point in time. Jinder Mahal and the Singh Brothers would be demolished by The Shield in a matter of minutes. And unless you count The Riott Squad, that's pretty much it in terms of trios, quite honestly.
It would have made sense for The Shield to have returned to vanquish a heel authority figure who was abusing his power like Corbin. But now babyfaces are in charge of RAW and the Shield has nobody to potentially feud with.
This is why I think reuniting The Shield is a very bad idea.