Should end the brand split: "Branded" PPVs don't always satisfy the fans
With so many stars split into two camps, there are advantages and disadvantages.
While the advantage to keeping the stars separate could be seen as the ability to maintain storylines for longer and to keep the shows more interesting by having multiple champions, the disadvantage is less obvious.
Take AJ Styles, for example. He's faced nearly everyone on the SmackDown roster in a title bout, some of them multiple times. However, he's limited by the brand split as to who he can face off against. While fans might salivate over a match between AJ Styles and Dolph Ziggler, the fact is the match can't really happen so long as the brand split is maintained.
This is why the single brand PPVs for WWE don't fare nearly as well critically or financially as shows that include both SmackDown and Raw, such as WrestleMania. Fans would like to have a chance to see ALL of their favourite WWE stars, not just the ones from either the red or blue brands.