#4 Night of Champions
Yeah, that's right, Night of Champions and not Clash of Champions. This event is semi-taken from the WCW days and has been around since 2008, and since then it's been extremely hit and miss in terms of the quality of product they've put out. When it comes down to it rewording the event as Night of Champions was a solid idea, but pretty much everything else they've done since has not been.
The WWE has a great concept on their hands which could be big enough to launch the PPV into the stratosphere of the big four. The big issue is that with the stipulation being all championships are defended, it makes it seem odd when the same thing occurs on various other shows. For example on six occasions since the introduction of the event, another PPV has also included every single title in the company.
This is very easily solved - make things even bigger. With the brand split, have Night of Champions also be a dual-branded PPV where every belt is on the line. Whilst that would mean there's a high quantity of matches, you could put a few either on the Raw/SmackDown beforehand or even on the pre-show. Whatever the case may be, it'd be great for the lineage of this pay-per-view to really mean something in the history books.
Speaking of the history books, this final entry will certainly have people talking for years to come.