That is quite the pedigree and shows that James Wan is well suited to coming aboard the existing DCEU and working within the boundaries of what Warner Bros. is building to create an exciting new chapter with Aquaman.
So it is natural that Warner Bros. would want someone who has proven adept in franchise filmmaking to take on Aquaman (and hopefully carry the DCEU forward).
As Toby Emmerich told Entertainment Weekly, James Wan has more than proven himself in this arena.
Like pretty much every studio, Warner Bros. is concerned with franchises, and its DC properties and the DCEU have the most potential on that front.