I really, really find it hard to believe that people only played different Battlegrounds on weekends, sorry. I don't particularly expect it to come back, I already linked the reply that was left by a Developer regarding the change. If I was to hazard a guess, making it so the event happens every day, but only offers rewards on the proper days (if it was to come back, that's what I'd be looking out for.. you get the rotations and the PvP, but not the rewards, of course), might be too messy to automate.
I know about Battlegroups, but they were formed by servers with a cap of 2000 or so from all accounts I've found. Even if you were correct about it being seven (I couldn't find that number being mentioned), it would require all of them to be at almost the cap simultaneously to surpass what we have. Discounting the odds that it was less than seven, we have about the same of what you could expect in a Battleground, wouldn't you agree?