As far as IP's go, they're not really missing anything other than those two. And when those teams come back that'll more or less give us all the major players, with mostly very minor characters like Secret or Warlord
left out.
But the problems in the continuity are far deeper. We're still technically on a five year 52 timescale but Superman has been a parent for a decade. Conner Kent didn't exist in this history until a couple issues ago, and that's been a recurring subplot in a few books since Rebirth. The NTT era, and most of those characters, are still a mess. Donna Troy wasn't around when Dick was still Robin, Roy was still Speedy, etc., in current continuity. It's not just a matter of whether a story from thirty years ago "counts," its a matter of basic facts within the current runs and continuity not lining up with each other.
We're playing continuity Twister right now, with one foot in New52 continuity, a foot in post-Crisis, a hand in pre-Crisis, and a hand in completely new stuff. And DC did this on purpose with Rebirth, it's supposed to be glaringly broken right now and not make sense. Even if the plans and people in charge have changed, they still have to deal with this problem they made for themselves somehow.
I forgot Johns and Snyder were working on this as far back as Metal! Good recall man!