We're able to confirm the finish that WWE went with for the Night of Champions main event, with the Seth Rollins interference, was the finish they had planned before Roman Reigns' health issue.
Here were the original plans for the show, pre-Roman Reigns health issue:
Dean Ambrose was going to cost Rollins his match against Reigns, with Seth trying to "cash in" at the end of the night (with John Cena stopping him). This would then set up Brock Lesnar vs. Cena in a Hell in a Cell at the pay-per-view next month, blowoff Rollins vs. Ambrose, with Reigns moving on to Orton.
Not knowing initially how long Reigns was going to be out, the decision was made to stick with the planned finish for the main event.
As we've reported previously, with the pay-per-views only costing $9.99 instead of $54.95, WWE feels they have a lot more leeway with doing DQs and bait and switches in major matches.