Nobody will play 55 lvl warzones with normal commz when there are ranked Arenas with OMGMYEGORATING and ranked commz...
daily and weekly quests only work for regs. arenas are a part of reg Q. 4m's in reg Q are as likely to land an arena as a WZ and their competition is also just as likely. thus, reg arenas are going to be massively imbalanced with 4m teams vs. 4 pugs. that's far far far worse than 4m + pugs vs. 8 pugs. it's even worse than 2x 4m vs. 8 pugs cuz the 2 premades aren't necessarily in the same guild/voice.
meanwhile, quitting is endemic in solo rated. a quitter there is devastating to the team. almost guaranteed loss.
finally, why the hell would I destroy my rating with a fresh 55 by jumping straight into solo rated? it utterly invalidates the rating in the first place. good player or bad. premade or not. jumping into rated is a bad idea.