The fact that WWE superstars, for the most part, are exclusive to one brand – either Monday Night Raw or Friday Night SmackDown – and thanks to the WWE draft (even if it was a somewhat lackluster draft) were both done in an attempt to eliminate the problem of overexposure. Top stars within the company were typically the ones who suffered from overexposure because they were usually the people who were featured on both Raw and SmackDown some weeks.
The fact that they are all exclusive to either one show, or the other, and will only be seen once a week lends itself to making them feel more like special attractions. This means fans will be less likely to grow tired of certain superstars and assist them in the process of building a mystique to their characters.
Overexposure is a real thing in WWE; why else would the WWE universe have grown tired of John Cena? Because he went through a period in his career (between WrestleMania XXI in 2005 and WrestleMania XXIII in 2007) where he was WWE Champion for 20/24 months, and fans just wanted to see others become champions too. In basketball terms, they kind of reviewed Cena as a ball hog (like Russell Westbrook, a ball-dominant point guard). The WWE universe ultimately grew to love Cena’s personality over the years.