Below here I would like to present a couple of ideas for how the Shield will end. I will try to avoid setting time stamps to it and instead focusing on what will transpire within the group itself.
The Shield ending
#1 – Ambrose snaps
In this scenario we will see the human emotional roller-coaster that is Ambrose derail a bit. As time goes on, Ambrose becomes more and more mentally unstable and as a result more and more violent and vicious, taking his methods of spreading the message further and further week-by-week, every attack becoming more and more violent. Seth and Roman will notice this and try to talk with Dean about it only to be told off. As a result of this Ambrose falls even further off his rocker, fearing that his teammates are going to betray him, paranoia sets in and he takes out his fears and anger on the wrestlers they attack.
Eventually it becomes too much for Seth and Roman and Ambrose’s paranoia becomes a self-fulfilling prophecy. The Shield attacks a wrestler and Ambrose is out to seriously injure him, setting him up to “end his career” using some kind of object (chair, steel steps, table etc). This is where it becomes enough for the other two, who step in between. Roman stands in front of their supposed victim and Seth tries to get through to Dean, trying to talk him down, as a response to this Ambrose attacks them, delivering the first blow and splintering the Shield. Roman and Seth use the numbers game to overpower him and the Shield comes to an abrupt and emotional end which leaves Ambrose alone in the ring cursing his two former brothers in arms. This turns the Shield into two entities, Ambrose as an insane one man army, adamant to keep up his mission of fighting “injustice”, injustice that he now says has taken his friends from him. No longer able to see what is unjust and what is not he strikes out at the WWE as a whole. Rollins and Reigns instead get a new mission, stopping their former friend. Rollins is the voice of this new incarnation with Roman acting as the muscle. This is a feud that I believe could make all three of these men stars, the total destruction and downfall of the Shield, an insane Ambrose against a system that only he sees and his two friends trying to stop him. Reigns and Rollins can themselves splinter from each other down the road, citing different opinions on how to stop their friend, in my mind setting all three men up for great careers in the WWE.
#2 – Rollins turns on the group
This feud sees a similar build up as the first one. With Ambrose becoming more and more vicious and deranged, only this time Reigns has no problem with it. Rollins is the one showing doubts, perhaps these seeds of doubt are planted by a confrontation with a veteran or hall of famer who claims to see so much potential in the Shield, but claims that they are wasting it with their vigilante act. This sticks with Seth and over the weeks we see him get more compassionate for others and having qualms with the Shield’s methods. He might even seek out this veteran for a talk. Then we come to the breaking point, same scenario as last time with Ambrose about to injure a wrestler. Seth steps in front of him and tries reasoning with him, claiming that the Shield has grown corrupt and lost its way. Ambrose and Reigns attacks Seth for suggesting that they change their ways and Seth puts up a valiant fight, the numbers game overpowers him thou and it ends with Seth lying in the ring. Ambrose, standing with Roman up in the crowd then claims how Seth has grown weak and how he has become just another part of the system. The Shield is broken. This leads to Seth trying to redeem himself and trying to stop his former friends from injuring others. This sets up a two-step feud of sorts. Ambrose at the start of this goes after and claims a title (IC at the lowest and in this hypothetical scenario it has had its status reinstated) and Seth tries to stop him, only to do this he has to go through Roman, this in itself takes one or two pay per views for Seth to accomplish. Once he has defeated Roman he must qualify to challenge for Ambrose’s title. This then sets up a personal rivalry between two future stars, allowing Roman to gain some momentum of his own outside of the Shield.
#3 – Roman gets an ego
As the Shield keeps demolishing the roster, the GM’s decide that they need to be confronted by some older talent. Enter the veterans. The veterans try talking sense into the younglings but it always ends with Rollins and Ambrose sicking Reigns on them. Eventually this starts to go to Roman’s head, that he is taking out all these legends and hall of famers. Eventually one of the older wrestlers (in this scenario I will go with Christian) steps up to plate and challenges Roman to a match instead of a backstage fight. Christian uses his smarts and guile to outsmart Roman, stealing the win. This gets Roman in a rage, breaking the cool posterior of the Shield’s giant. Roman sets off on a mission to get back at Christian, effectively leaving Seth and Ambrose in the dust, not caring about the Shield, only about defeating the sly Canadian. Seth and Rollins thus start getting beat down themselves since other wrestlers now fight back since Roman is no longer around as a physical deterrent and tank. This leads to Seth and Ambrose getting in fights with each other, splintering the group even more and causing a rivalry to be born between the two (Seth as a face and Ambrose as a heel). The two go their separate ways after feuding for a while to get each other over some more and Roman keeps feuding with veterans to keep sharpening his ring skills.