This sounds like a pretty good idea. Personally, I really like EP's, but it's a shame that it's an old season activity.
About the map issue, why couldn't they use the normal map (somewhere like BrayTech Futurescape) and close off some areas so you can't get out of there? Surely couldn't take too long to program.
well the problem would be if you match make, you would instantly fill a social area and if there were existing guardians there it would cause an issue. But, I could see having a match made instance and just shut down the doors too. So it would just spin up a new instance of the futurescape or Glacial drift and then just close off entrances/exits with like that hive mist wall. Then drop all 9-16 players into that area, then anyone that hops into match make just fill in the empty spots.