Unlike the current Marvel Legacy branding, last year when DC Comics kicked off their DC Rebirth initiative they chose to only return Detective Comics & Action Comics to their legacy big numbering while everything else began with a fresh new #1 issue. By the end of the year, that could be changing.
As reported by Newsarama, the publisher has commissioned variant covers from Tony S. Daniel for Superman #34, Wonder Woman #34, Batman #35 and The Flash #39 that are billing the issues as the 800th adventure of Superman, 700th adventure of Wonder Woman, 800th adventure of Batman and 700th adventure of Flash respectively.
There is no real indication that the titles will actually change to reflect those number and these very well could be just variant covers. It seems very likely though that at some point DC might consider reverting some of these characters to legacy numbers to showcase their history more like with Detective and Action.