As far as I can imagine, the primary limiting factor is going to be whether or not dungeon design allows for people to forgo tanks to a larger degree than Heavensward's. Given SE's drive to remove their own mechanics (virtually any form of CC), it will probably be difficult to run nontraditional parties in order to escape queue times, but even that would require running with 3 friends so it's not like that would have been some sort of saving grace generally.