The solution is really simply, group premade teams vs premade teams. Equal footprints for everyone involved. And leave solo queue for the solo queuers.
Should be perfect for everyone involved, except you. Because it's quite clear that you think that if you've gone through something, unfair or not, everyone else should do the same as well. My god. If the world worked that way, we'd still be in the stone age.
That's a terrible solution.
Premades are not all equal, hell, they aren't even all the same size! Splitting premades and soloers in to different queues would be a massive fail. All it does is split the problem in two. The warzones would still be unbalanced. The gear levels would still be different. The skill levels would still be different. Nothing would change except you'd realise you were wrong, but you'd ignore that and focus on something else.
The solution is global ranking and matchmaking system. Just how ranked works now, but apply it to absolutely everyone. Then balance teams according to individual player's ranking. A proper ranking and matchmaking system will take care of gear imbalance, skill imbalance and premade balance as long as it applies to everyone.
Every other solution suggested in this thread is half-arsed in comparison.