The only solution is to introduce a very specific solution and that is to allow hydralisks to be a good counter to mutalisks by giving them regular (aka double) damage to very light armor types of which mutalisks now possess this "very light" armor type.
This would allow for more grounded-play in ZvZ and would make lurkers a viable defensive option to slow down the pace of ZvZ to a considerable rate without altering the fundamental gameplay or style of ZvZ.
None of this can break Zv.Z as mirror-matchups cannot be broken in terms of balance but merely broken in terms of level of depth or choices in options or fun value.
I know this is a very specific solution. But it seems to be the only one unless Pete Stillwell has a better solution.
This can be a good solution for the rock, paper, scissors scenario that exists at high level Zerg vs. Zerg play which unfortunately ends the fun. This would positively raise the skill ceiling for zerg vs. zerg play which would extend the rock, paper, scissors scenario so that it would take more time before ZvZ players would reach that unfun ceiling.
This is my thought.
What do you guys, especially at Blizzard think? (They deleted my post because as we all know they want to protect their reputation more than anything aka the starbow shutdown so maybe you guys could push this idea out there for the benefit of the game and science.