#3 There are no clear heels in this feud

Neither Ronda Rousey nor Becky Lynch is a clear heel going into Wrestlemania 35, even if the story is about two women who had different career paths but reached WWE nevertheless. Ronda was handpicked by WWE management due to her mainstream attention, whereas Becky had to put in 300+ days of work every year for the past few years yet did not make regular PPV appearances.
Both of the women are non-heels who have their reasons to win. Thus, adding Charlotte, who is now a heel, would give more versatility for planning this three-way feud. Although WWE has done various face vs. face dynamics for the main event of Wrestlemania before (the most relevant example being The Rock vs. John Cena storyline from 2011 to 2013), adding in a heel would only help to make the build up more interesting.
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