#1 One week would be too less to build a match this big
Whoever operated the forklift and dropped the scaffolding on Roman Reigns, one week is way too little time for a proper story to brew. That is especially the case if the man in question is Daniel Bryan, as has been reported. Now, a match between these two stars is way too huge to have a build of a single episode of SmackDown. Reigns vs Bryan is a match that could feasibly main event WrestleMania. They are the two biggest full-time stars in the company.
It would honestly be slightly foolish of WWE to book a match of such magnitude without a proper build, on a card that's stacked with huge matches with much stronger stories. Despite the talent that both superstars possess, this match could get lost in the shuffle on the 5-hour Supercard especially with the lack of storyline behind it.
WWE should ideally let this angle play out for a couple of weeks and reveal Daniel Bryan as the attacker after SummerSlam. Then we can build to a match at Clash of Champions or better, SmackDown's debut on Fox. It would only benefit the storytelling in WWE at a time when it has improved a lot.