Lets be very, very clear about something here. The majority of people actually interested in regularly doing 8v8 Ranked again have left the game, and those that are still here are doing 4s because *they enjoy the competitive nature*.
You remember that huge 'bring back ranked 8s' thread when they got removed? The stupidly high majority of the posters in that thread *never* did 8s. And if 8s were brought back tomorrow, the majority of people saying theyd want to play would quit them within a week of losing to better teams.
I am not talking about the entire PvP population. I am talking about the insanely small group of competitive players that remain in this game. That population cannot afford to be split any further, because it is already below a sustainable number with only 4 man groups required to participate.