Well vrai last time we did this, we actually unbanned basically everything bar cover legends and Arceus, Mewtwo etc trying to make it so not every last little thing was banned and to open up some options for all play styles (iirc we even allowed Drizzle Swim or some form of it ? Maybe one sser per team i forgot). That metagame WAS very balanced, sure a couple of things like Doexys and Shaymin-S werent but yeah. However all that happened was people like Syndrome trolled and people didnt even want to try it, that is why it failed last time and why as nica said "i got pissed off" lol.
Idk maybe that would be a good starting point again ? But with Deo and Shaymin banned too and stuff like Thundy-I, Exca, Blaze, Manaphy etc all unbanned.
Anti makes an excellent point though, people need to actually stick to this or it will fail once more.
I also agree with Karps point of view, you really should have to think about breaking through teams and not just to quote him "throw Tar Keldeo and Landy at things" or hell just using something with base 140+ attack. I think that is what makes a balances metagame more than anything. These days you literally dont even have to use your brain, just click the strongest STAB move and watch things die.