We have premade versus premade already, its called ranked warzones. It failed because it split the (small) pvp community in to two separate queues, making queue times longer (big negative) and highlighting the massive differences between good and bad premades to the point where all bad/average premades stopped queuing. You're suggestion has already failed, so I see no reason to repeat that failure.
For the record, we are after the same thing: fair pvp matches
However, your method has already failed (segregating the community) because it doesn't address the core of the matter - player skill. Player skill is amplified by gear and premades but ultimately player skill should be the ultimate balancing method, and a ranking system is the closest we can get to measuring player skill.
If we split premade and solo queues, I guaruntee that within a month the premade queue will be pretty much dead and the exact same problems we have now will still exist in solo warzones.
I agree, most premaders are genuinly afraid to go up against other premades. BW should by defualt send all 4 man groups to the ranked wzs and have all 8 man teams with two 4 man premade groups go up against other 8 man two 4 man pre made groups. this will allow solo quers to go up against pugs and all of those whom premade go up against premades. they should also have a cross server que. this is supposed to be a AAA MMO and it does not have a cross server que, that is sad.