WWE may think that there is still money to be made with a rematch between Roman Reigns and Randy Orton, but this has been done many times in the past and run its course.
What Reigns will be doing at Night of Champions doesn't seem to be completely set in stone, although the cinder blocks may be pointing toward a match against Seth Rollins.
One of the obvious angles to play up in this feud would be their former partnership as members of The Shield, with Reigns seeking vengeance on behalf of his fallen comrade, Dean Ambrose. With Ambrose away filming a movie, it's unlikely that he will be facing Rollins at this event, so Reigns can step in and give Mr. Money in the Bank a worthy opponent.
The trick with this feud would be to balance the strengths and weaknesses of the two men involved.
As a cowardly heel, Rollins has a built-in fail-safe for both wins and losses.
Should Reigns need to lose this match at Night of Champions, he can be booked strongly leading up to the event and then lose by some fluke interference from The Authority. This would possibly set up the next opponent for Reigns at Hell in a Cell, whether that be Triple H, Kane or someone else.
On the other hand, if WWE would prefer Reigns to win at Night of Champions, it is even easier to set up.
Reigns can continue to steamroll through the competition on Raw and SmackDown for the next few weeks while Rollins evades feeling the full brunt of the unstoppable juggernaut.
At each corner, Rollins will have Randy Orton and Kane to back him up and take the fall for him. After all, wouldn't the architect of The Shield would be smarter than to fall victim to his enemies and not take advantage of the backing of his faction?
Bonus points can be awarded if Ambrose is able to return at Night of Champions to help Reigns out when Kane or Orton interfere in the match.
This could even set up an admirable Hell in a Cell match where Reigns, Ambrose and someone else face off against Rollins, Kane and Orton in the cage.