Peter David probably takes over Aquaman much earlier - and given he made some of the biggest chances to the Aquaman mythos until the New 52, it's possible his merger of Namor/The Submariner becomes a part of that.
David is the one who introduced the "Seven Seas/Five Lost Cities" to the Aquaman mythology - this is from where most of the modern Aquaman mythos comes from, save some changes made during the New 52. David benched a lot of the usual rogue's gallery like Black Manta and Ocean Master, and most of the tension early on came from Aquaman's bastard son Koryak, leading a split-off faction of Atlanteans who disagree with Aquaman's quest to unite the lost cities - here that role could be given some much-needed bite by just having the Koryak role played by Namor, playing up his Atlantean roots against "the half-breed".
That could actually be an interesting long-running rivalry in the now joined Atlantis mythos, between Namor, the half-breed raised in Atlantis, and Arthur, the half-breed raised on the surface - similar to how Geoff Johns made Orm/Ocean Master a tragic villain/anti-villain in the New 52.