#2 Dean Ambrose has been going off the script
Roman Reigns beat a life-threatening disease to bounce back and return, in what seems like phenomenal shape. Seth Rollins has been a workhorse for WWE, to shows up to work, despite the fact that he's recovering from an injury. Dean Ambrose has been out of shape in recent months and has also gone off the script in previous weeks.
I mean does it make sense to ally with a man who did not stick to the script when he said 'slay The Beast' to Seth Rollins on RAW recently? You'll have two members of The Shield who're giving it their all and a third member of the faction, who simply does not care anymore.
It would just leave the audience with a bitter taste in their mouth, on the road to WrestleMania. I do hope I'm wrong and Ambrose begins to care again.